If you're looking to purchase a watch winder, you may hear the term turns per day, or TPD. Some watch winder salesmen may swear by turns per day, but it's really just a rough guideline. Basically, turns per day is the absolute minimum turns necessary to wind a watch from being completely unwound to being fully wound. However, watches set in a watch winder should not be constantly would, and it doesn't always need to be would 100% all the time.
Watch winders don't all work the same way, of course. The number of turns one watch winder needs to wind up a watch may be completely different from the number of turns another winder needs. Because of this, turns per day can't really be used to directly compare different types of watch winders. It can, however, be used to tell how efficient each type of watch winder is. Some winders may actually do too many turns per day for your watches.
There's no set number of turns per day that you should look for. Instead, you should take into account how much movement is necessary to keep the watch at least partially wound. You don't want it to run completely down, but at the same time, it's not necessary to keep a watch 100% wound, either. Generally, you want a winder that will use the least number of turns necessary to wind up a watch. This will avoid overstressing the winding mechanism and causing unnecessary wear and tear on the watch's movement mechanism.