In real life equipment wear and tear is a big deal. A broken sword can certainly limit the ability to fight, long distance runs with rags wrapped around your feet are no fun. How much wear and tear matters in a campaign should be balanced with the type of adventure being presented. Some argue heroic adventure shouldn't deal with wear and tear as it isn't; flashy enough but I hold that argument is empty as I recall the occasional warrior king to be traveling the countryside with a sword that must be reforged or a weapon the hero depends on breaking at a critical moment forcing the hero to rethink tactics.
Suggested conditions for equipment.
Functional: nothing to track, this normal equipment working well and in good condition.
Damaged: the equipment has been subjected to some distress. It should be considered to be -1 in quality; this modifier being applied to all variable rolls when the equipment is deployed.
Worn: the equipment has been subjected to repeated distress. It should be considered to be -2 in quality; this modifier being applied to all variable rolls when the equipment is deployed.
Broken: It's broken. No longer useable for it's designed task.
Quality of Equipment
Not all goods are made to the same high standards. The quality of equipment can vary by source of manufacture and are a great source for what to do with PC funds.
Poor: Low quality equipment. Poor weapons must check vs damage on any attack roll of 1,2,19, or 20 or be downgraded to worn.or break if already worm. Poor equipment costs 1/2 normal.
Common: pretty normal equipment. common weapons must check vs damage on ant attack roll of 1,2, or 20. Common weapons downgrade one factor on a failed save. Common equipment cost normal list price.
Good: decent equipment definetly a cut above normal. Good weapons should make a save on a attack roll of 1 or 20. Good equipment commands a 1.5 to 2 times normal price.
Fine: a notch above good. Afine weapon need only make a save on an attack roll of 1.
fine equipment costs 5 times list price.
Very Fine: top end for mundane gear. Very fine weapons should make a save on an attacke roll of 1.
Very fine equipment costs 12 times list price.
A craftsman with a proper set of tools and workplace can repair equipment at a cost of 1/8th per damage factor. Going from broken to functional is 3 steps of repair. A craftsman must be skilled enough to craft equipent of the quality they are repairing to actually repair such damaged equipment.
Wear and Tear Saves
Equipment save are made just like PC saves. If your game already has equipment saves use those rules with appropriate modifiers. If d20 based I recomend -2 for poor, +1 for good, +2 for fine and +4 for veryfine. Magicla bonuses add ontop of those save modifiers.
Game doesn't have a save. Go by quality of item: Poor 12+, common 9+, good 8+, fine 7+, very fine 5+ on a d20.
If yuo want level based saves use modifiers as per generic d20 saves.
Having equipment cards on mide i relaized there was room to put a check box for condition of equipment and to list the quality of equipment on the card withotu worrying about a player missing those details.Keeping track of such details without cards or detailed equipment sheets might be a chore indeed. For those striving for gritty and realistic wear and tear should be part of the game.