Just an easy question. Maybe it's because I'm weird, but I always feel like keeping all my 100% save files, even in those games that I know I'll never ever replay, instead of cleaning them to make more room for another file, or in the need of digital space.

Of course. Sometimes I even copy them onto another slot, in case one gets deleted.

I'll never delete my original first ever 100% save file for Super Mario 64. I would rather break my N64 controller in half.

Yep, always do

I did. I used to treat them as some sort of "Trophy/Achievement" back in those days when none of those existed.

See, I have like a similar feeling towards it. I'd rather have something else broken than my file lost.

I always go. if the game only has 1 slave slot I don't replay it, unless I can emulate it.

No. If I like a game enough to 100% it, it means I'm likely going to play it again and try to 100% it again.
Also, I have a strange proclivity to stop playing a game about 95% of the way through the game if I'm going for 100% completion.

Depends, most times I just want the satisfaction of knowing I completely a game fully.

I do this often, but tbh it is not that important for me.