Frankly, regarding Encounter Area "A" of the Keep on the Borderlands module, I can't see how a player part of five characters could survive. From the group that jumps the party just before reaching the entrance, through to the common chamber, there are 65 kobalds and 18 giant rats, altogether. These have a total of 210 hit points. Though only one of these has more than 5 hit points, and most have less than 4, it would still require a total of 83 successful attacks to kill them all, more than 16 rounds of attacking, assuming no player character missed or rolled less than the number needed to kill. In the meantime, the number of attacks the kobalds would have in their turn, even as they died in heaps, would probably kill the party unless the party were somehow possessed of above average armour for a party of 1st level.
At least, if I were to run it. The huge distances between rooms were obviously a set up for the party to be able to dispatch the kobalds in isolated groups, in tight spaces, helping to balance every combat in the party's favour. This, of course, makes the lair fairly useless to the kobalds. They'd do better if they were camped outside on the grass, so they could attack any invaders en masse. The only reasonable argument for humanoids to live underground is to construct that underground in a way that makes them impregnable ... not in a way that divides up their numbers and scatters them so a small group of pillagers can butcher them.
Let us, however, ignore all that and allow that somehow the players have won. After killing the forward guards, they've moved through the lair and cleaned it out.
To remind the reader, we suggested giving information about the dungeon to build the player's expectations. We suggested that this dungeon was one to which a princess was kidnapped, and that although there were rescuers, neither they nor the princess were ever heard from again. This doesn't seem to fit with the presence of a lot of kobalds, that somehow mere 1st levels could dispatch. For the sake of continuity, this is a matter that has to be addressed.
But first, consider the party as the last kobald falls. Their first concern is not going to be with the unremarkability of the kobalds, but with treasure. Therefore, let's dedicate this post to treasure and pick up the continuity later.
[as a DM, we have to think about more than one thing at a time, but as a blogger, we shelve whatever we want]
The treasure given for the kobald lair in the Borderlands module is an average coin total of 89 gold, 235 silver, 22 electrum (2 electrum per gold) and 203 copper. In addition there are three objects amounting to 1,650 g.p. (though the description of one object clearly defines it as being worth 400 g.p. and 300 g.p. at the same time; an error).
Assuming the old AD&D experience award for combat, each kobald or rat is worth 5 x.p. +1 x.p./hit point. The chieftain might have a rating of 10 x.p. +1, but that's arguable. All experience, counting coins, equals 2,383, assuming the AD&D rule of awarding 1 x.p. per g.p.
For five 1st level characters, this is a very shitty haul. The odds are decidedly stacked against them, and if I were running the players would definitely die, but the total treasure given, divided evenly among the party, gives the fighter less than 25% of what's needed for second level; the mage doesn't get as much as 20%. A thief gets 38%; a cleric, 31%; a ranger, 21%. It means that for most of these characters, they'd have to fight the same total combat, with the same skills and hit points, four or five more times just to reach 2nd level. That's appalling. It indicates tremendously bad design, from the number of kobalds met to the amount of reward for killing them, all of that past the layout of the rooms and virtually everything else about the encounter.
These were things that my early D&D companions and I spoke about with nearly every running. What is too much treasure? What is too little? Gygax talks about this in the original Dungeon Masters Guide, but personally I don't believe he mastered the solution, or perhaps his head was so up his ass he couldn't master it.
I don't agree that automatically giving the players a level for having beaten the kobalds is a good solution. It sounds like one; and for games with non-tactical designs, it's nearly always the only solution, since the one alternative is for the DM to produce a number out of the air and go with that. Unfortunately, not every combat is "level-award" worthy, and they become less so once the players advance past fourth level. For myself, I have zero desire to increase a druid's level from 12th to 13th on the basis of one encounter, then from 13th to 14th on the next encounter. This drastically cheapens the meaning of level and fails to give the player any sense of hard-fought-for accomplishment, as all they need do is pick a fight they think they're sure to win. And if I punish them for that by not rewarding them with a level, because the fight wasn't "dangerous" enough, then they've just fought a battle for no good purpose at all, encouraging resentment of me and the game. This is encouraging a bad pattern.
I have created solutions that reduce the problem, and written about them both here and on my wiki, but as I've said before, this is about your solution as a DM. You need to find a way to reward treasure without your influence deciding by fiat what treasure is given.
When you figure that out, please tell me ... because I haven't found that particular solution yet. After the designing of many tables based on elements like how long did it take the players to overcome the obstacle, how much damage did they take, how many creatures did they face, what ratio exists between the players' average level and the monster groups total hit dice, etcetera ... and every calculation I've made along those lines has proved unsatisfactory. The result is either too little treasure, or too much.
The only solution I've found is this: give what seems right. Unfortunately, "right" is an extremely squidgy subjective thing, requiring the DM to understand elements of the game according to an esoteric perception accumulated through thousands of hours of play. And I've met many DMs who, despite those thousands of hours, don't seem to understand one damn thing about the game at all.
Advancing some principles underlying my convictions on this would be appropos at the moment, so I'll try ... but these are not things roaming through my mind during the game itself, when I have to produce a number from the air and make it the right number. That I do by instinct.
To begin, characters never deserve to go up a level. The value of the level itself is that it provides an option in play that did not previously exist: an action, an extra spell, a type of spell, meaningful improvement in some former ability and so on. The player should NOTICE this change sufficiently enough that it's highly memorable from the last time the character advanced. If the effect of the level change is so meaningless that the player failed to notice, then he or she won't care about the next change.
To put this another way: Geoffrey entered the campaign at 1st level and found that in each combat he barely had enough hit points to sustain two hits. He found himself at zero, or less than zero, on more than two occasions and it produced a feeling of wanting to hold back rather than wade in. Then Geoffrey went up a level; he rolled his hit points and found, lo and behold, he could sustain three hits instead of two. This appealed to his consciousness the first time he took a hit and found himself down to 9 hit points. "Hm," thought Geoffrey. "I've been here before. I've fought quite a few battles where I started at 9. I'm doing okay. It's good to be 2nd level."
It matters that Geoffrey spent enough time at 1st level to feel what it's like to be 2nd. It matters that Juliette discovers, upon reaching 2nd level, that she has two or three spells to choose from, instead of just one or two. And while we're on that point, if all of Juliette's spells are the same spell, then the difference between two and three isn't that great ... because it's not noticed until the END of the combat, rather than at the beginning, like Geoffrey's hit points. By the time Juliette gets around to noticing she still has one spell left, a lot of the combat has happened and that third spell feels like a bit of a let down.
I hope the reader understands how these tiny nuances affect play. If Juliette goes from two different spells, that do different things, to three different spells, it doesn't just increase the number of times she can cast magic missile. It affects the number of different situations she can counter, getting rid of her being the one trick pony she was at 1st level. Unfortunately, the choice by many game designers and DMs to allow players to simply up the number of times they could cast a favourite spell butchered any possibility of that character's growth as an INVENTIVE influence on the campaign. Not to mention that it drastically limits every other character as well, who know that the mage is going to bring the thunder over and over, no matter what I do as a fighter or a thief. So who cares?
Maintaining this adjustment from a lower level to a higher level says that we cannot give so much treasure that the players simply jump level after level without gaps between. Thus, the kobald lair described shouldn't include so much treasure that everyone in the party goes up a level, especially if this is their first encounter in the campaign. Even if the battle almost killed every one of them, even if they find they've got a collected hit point total of three, with two of them unconscious, this does not mean they "deserve" to level. They deserve to know that this is what life is like at 1st level.
I couldn't rightly say, however, how much treasure ought to be given, because that depends on a lot of things. First, that the kobalds ought to have an amount that fits with their presence in the game world. We should calculate treasure according to logical assets. At any given time in my life, the amount of money I held in a bank account was never meaningful compared to the value of the things I owned, that surrounded me. Everybody understands this, when they finally accept that the bed they're sleeping on will no longer do, and they'll have to find a thousand dollars or more from some source to get another one. That means that bed has been worth a thousand dollars to us, every day, just because we didn't have to replace it ... even if it's a pretty lousy bed. The same goes for the computer, the wall screen television, the car, the cups and saucers and silverware in the kitchen, our tools, our towels and linen, the vibrating toothbrush we use at night and so on. It's a long, long list, and if you had to replace everything from scratch, you'd be damned glad that your friends have extras of this stuff and could let you have it for free. Most of us have an extra garbage set of silverware kicking around in a box somewhere.
It makes no sense that the kobald chieftain has a gem worth 1,200 g.p., as described in the module. His lair has no means to make metal weapons, which break, or leather armour, which breaks, or even the animals and the ores from which to make leather and metal. He can't count on all the kobald weapons and armour, and all the other things besides, to endure every day for years. Plus, the very existence of the gem is like asking someone to kill you and take it. That's why, if you suddenly won a lottery that gave you $1.9 million, you wouldn't spend it on a Bugatti while continuing to live in your second-rate downtown apartment, trusting that of course you can park your car on the street. You want to hold onto a gem worth 1,200 g.p., you better have more than 8 h.p. and a non-magical battle axe that inexplicably does 2-8 damage, unlike every other battle axe in the game's rules.
[if we give him a 17 strength, that would be 2-9 ... with a better average damage, and in keeping with game rules. sheesh]
So, forget the huge gem and spread three times that amount throughout the whole lair, sinking it into tools, more valuable stores, a bunch of smaller more negotiable objects like gauntlets, lamps, combustable oils, bottles of medicine, semi-valuable chests for holding keepsakes, totems or goblets; and putting dozens of silver rings into most of the upper scale residents throughout the lair, that the players can obtain only by taking a knift and cutting them out of each kobald ear. Perhaps the chieftain has nine of these altogether. Makes for a cringing moment, but I've never known a party whose greed wouldn't overcome that discomfort.
I'm certainly more likely to give more treasure if the players had a harder time. Is that logical? Yes, as a matter of fact, it is. If the creatures are hard to kill, they've survived longer, and had more time to accumulate stuff. This particular kobald hive, with it's 65 kobalds (not counting non-combative children), is quite a little collection of persons. It must have taken some time to organise themselves and divide their labour ... and if it turns out that they're such a bunch of whiffs that a 1st level party wades through and wipes them out in a couple dozen rounds, then I guess those kobalds were lucky to have lived as long as they did. On the other hand, if a third level party has so much trouble with them that they have to give ground, run away and then lick their wounds for a while before returning and recommencing the battle, then I guess those kobalds have probably fought off a few other beasties in their time.
Consider that 3rd level party: mage, fighter, ranger, cleric, thief. Total experience earned by the player party, assuming they're all halfway between 3rd and 4th, is 28,500. If half that is from treasure, and this group can't take on a group of kobalds the first time, there's an argument to be made that the kobald's assets should rate somewhere around 14,000 g.p. 'Course, if players want all that to be in easy-to-carry coins, and not doorlocks and iron spikes for the pit, or brass fittings around each table and chair, or bits of ivory kobald cuticle prongs, or nice linen sheets for 65+ beds — and are therefore ready to leave a lot of wealth just laying around, ignored, while carping about the fact that there's only 1,400 g.p. in coins, gems and bits of jewellery, then that's not my problem, is it? Treasure is only treasure if recognised as such.
And it's not my purview as a DM to put a price tag on everything.
This, I think, is all we need say about treasure for now.