If using butter for bread I've just always kept it in room temp in a little sealable box, it doesn't go bad. But the butter we use here is always cultured, afaik butter in the us is not so I would assume it might go bad easier so your anxiety might be valid.

Same with eggs, they are not washed here so I just keep them on the counter.

Making cultured butter isn't terrible hard though, have made it a few times. Just takes time.