I always keep them all until the very end
I prefer to keep them until the very end.
Though I do end up leaving one effect behind due to the glitch on the MOTHER-like world
I keep them 'till the end because it's actually the last step before the ending. You can't get the ending if you don't trop them, so it's a "well, it's been nice and now I feel I've accomplished something" feeling (or ritual, as other anons pointed out) which fits the most what comes next.
Oh? What glitch is that?
Oh, that! I thought you meant like, an actual glitch-glitch.