I'm solidly in the "use" camp. The only ones I might think of "collecting" are actually the sentimental knives. Like the one handed down to me that was my grandfathers brothers (died as a boy, kept as momento by grandfather, now mine), my original boy scout knife, etc.
Everything else is mostly for a specific purpose, so while I may have more than one knife, each one does its "thing" (take to church, take camping, edc, wood processing, carving, etc). And as of right now I really only have one redundant blade, and one blade I'm not using much. Both of those I'm thinking about getting rid of/gifting. I think if I counted everything, I'd be around 15.