Yes, I do let the number run and add on. When I reach 10,000, the folder name automatically change to reflect the milestone. Like this, I know how much photos my digicam has taken, and estimate it's MTBF.
give the guy some credit... for all you know he's a pro photographer. even if he isn't, he might be just about the most creative guy you've ever known.
I more or less lost count.... save by the dscn/img #. And add the number of times I reset that counter.....
Keep about 70% of the shots, print (real keepers) around 10%..... Really good ones, perhaps 1-2%.