Taking unpaid time off in startup?

How common or acceptable is it to take many weeks (or maybe even few months) of unpaid time off in a startup that is past the initial phase (3+ years)?

I work in enviroment that is not as stressful I think, whole team works remotely. Co-founders are reasonable with work-life balance. But still I find it hard to pursue much of anything else or even to keep all parts of my personal life in great order (as I would wish). I feel like its weird to even ask for it, like it's expected to work 100% and just take bit of vacation here and there, but why? Even from the company perspective, I might be able to regain some spark and make the paid time more worth it.

I think sometimes people do this between jobs, but in a job that is ongoing for many years. How do I make a space for that?

How do other people come to terms with this? And how do you spend the time off to properly "restart"?