Here is an idea that get rid of having a hard limit on any items.
Here are the mechanics.
1. There will be no upper limit on how many an item can exist on game.
2. The percentage of popping an item goes down with the number of existing item currently held by players.
3. The timer on the items determines the value of the item. The longer the item exist, the higher the value is. This will affect the following:
A. Rent is directly proportional to value.
B. Repair cost is also based on value.
4. The interesting part, the base value of the item is then multiplied by the number of existing items in game.
So what are the advantages of this system?
1. Everyone has a chance to pop real we equipment. No more limit one or 3 items. Mobs will not be naked a month after wipe.
2. You better keep the freshes eq, hence you better visit those zones.
3. If you are willing, you pay the price of keeping old and second hand eq. Which can get expensive real quick.
4. Which also means that it may not be practical for a single player to hoard all the equipment in 10 of his multies.
Downside?
1. Your high value eq will be deadbeated real quick in rent.
2. Even if you are legit single player, you might need to refresh your eq or earn tons of coins to not deadbeat.
Downside isn't really downside if there is always a chance the eq will pop inside zone.