Because my hair is very long & very thick I have to wear a headband to bed to keep my hair out of my face. But if your hair doesn't bother you when it's down then I don't think it will hurt it. My son has a Mohawk & he has to be very mindful of how he sleeps depending on of he's wearing it fanned or IN liberty spikes. Sometimes he just removes all the glue & wears it natural to sleep. If your worried you might try a headband because a ponytail can be damaging
It depends. If I'm using a new product to make my hair less frizzy, my face tends to break out if I don't have my hair under a sort of night cap while sleeping. If it gets too long, it's also bothersome for me.
Ponytails and braids can be damaging. What the other two answers suggest seem reasonable. I wear my hair loose. When it gets too long I wind up getting it caught under my arm when I roll over, lol. That's when I know it's time for a trim ;)
I would say yes it's good.
I would recommend pulling it back seeing the oils from your hair which are touching your face while you sleep can cause breakouts even if its just washed. But other then that nothing is wrong with sleeping with your hair down. If you do wear your hair up wear a wrap around headband seeing it is less likely to take some hair with it when you take it out