Depends a bit on the type of cloth and the season. If my wrists drip sweat onto the edges of the pockets (where I keep my hands a lot) in the summer, I'll suck it up and clean more often. That's less of a problem in winter, and I can generally stretch the dry-cleaning out to the end of season. That would be about 15-20 wearings. Maybe an intermediate one in January to freshen things up a bit. Steaming and a trip through the Corby trouser press can postpone that a little.
The Brits and some Italians make a fetish about never drycleaning anything. That goes too far, I think. But they have a point. I do have some garments that I've never had dry cleaned-- brushing, airing and touchup pressing covers most sins. Among other things, a limiting factor on garment life is number of drycleanings. Not everything is designed to last a lifetime, but good tailoring is not meant to be disposable, either.www.8savilerow.com/caring04.html