Suppose we try this.
Everything that the player buys is assigned a half-life in days, this being the number of days that the item is expected to function so long as it is maintained and kept in good condition. Items like food have very brief half lives, sometimes only a day, while other items made of metal or stone have very long half-lives. Items that are better made have longer half lives than cheap items.
Every item loses a day of it's half-life so long as it is put to normal use, whenever it is carried or carted or packed on a journey and if the item itself is perishable. If the item is put to unusual use - meaning that it is strained or applied in a manner for which it was not constructed - then it loses more days than it normally would. For stone or metal objects we would roll 1d4+1, for heavy wooden objects 1d6+1, for flimsy wooden objects 1d12+1 and so on. Since flimsy wooden objects would have a shorter half-life to start, constant use of them in this manner would quickly cause them to break.
Low wisdom characters would increase the half-life of an object more rapidly than smart people. Every character could roll an wisdom check for every item they possess every day, even items that a sitting peacefully on a shelf (the unwise character decided to pick it up and toss it purposefully in the air just because) and for every point by which the check fails, that number of days are lost from the item's half-life.
Once the half-life is expended, then every use of that item requires a saving throw against whatever circumstance to which the item is put. If the item is rolling around in the character's backpack, then a 1 rolled on a d20 at the end of the day indicates the item is broken or unusuable. If a weapon past it's half-life is used in battle, then every round the weapon makes save against normal blow. Not just when the character hits, but every round, as it's assumed the weapon is used to parry the enemy also.
Half-lives could be kept in the open, as the item would develop nicks and scrapes and show wear and tear. The actual removal of days could be programmed, so that as a date was added, the program would calculate the number of days and the stupidity factor for each character's stuff (we could even have a 'stupidity fallout' effect where unwise characters break other character's equipment).
Then we could just sit back and watch all the stuff in the party break, one by one, causing the players to question whether or not that five-level dungeon was truly worth it.