I’ve been doing this since CoOViD. Previously I never used butter because it’s too hard from the fridge and “everyone knows” you need to refrigerate it.
However I started doing a lot more cooking, so it’s always been finished before it goes bad:
FDA recommendation 3 days on counter
“rule of thumb” 1 week on counter
some streamers claim 2 weeks
I’m not even sure what “going bad” means for butter. I have seen it change color so the outside is darker than inside, and threw it out. But ive never noticed an off taste or smell.
I live in a hot enough climate I can't do it all year, but my butter is out except for summer. I keep it in a container that I can pull a vacuum on since a lot of spoliage is basically oxidation.