I keep a log of how much and what caliber ammo I shoot at the range.
It was suggested to me by my CCW instructor as a prudent move should I ever be involved in a self defense court case, if I can prove I regularly practiced and was fully competent with that particular firearm it would be better than if it was a gun that I seemed to rarely use and was unfamiliar with.
But there is a second reason I log my range visits, there was a thread here earlier asking for data on Kahr firearms and numbers of rounds. The answers were all ballpark figures mostly. It is very useful to know how many rounds your gun has fired, even if you bought it used. You can predict any spring failure or other replacements.
It takes me a minute to write down the information each time, and about 5 minutes every page to carry the totals over.