Have Stuff Wear Out

The normal problem in virtual worlds is inflation. The effects of this are alleviated somewhat if players have many ways to be separated from their cash. The easiest way to do this is to have stuff wear out so that replacements have to be bought. This hands money to NPC vendors or (if goods are bought from PCs) to NPC miners/farmers. If PCs do all the mining and farming too, it’s still of some use because it encourages trade; it’s best as a money sink, though. It helps keep scarce items scarce.

Players see it as a money sink, of course, which makes them suspicious. It’s basically a tax on action. However, as long as you make it “realistic” you can get away with it: Shields used in combat really do receive a battering, but you’d be hard-pressed to justify why a ring wore out.