Generally, sleeping in an afro human hair wigs is not recommended, though much of this depends on the material of the wig and just how comfortable you will be in it. Here's why removing it is usually better:
Preserving Wig Quality: Notably, Afro wigs can lose their shape and texture, especially if one sleeps while wearing them. This is due to the friction between the wig and your pillow, leading to tangling, matting, and frizzing. Over time, this can appreciably cut down the life of the wig by requiring its replacement much more often or frequent expensive maintenance.
Hair and Scalp Damage: Wearing the wig for extended periods of time, even at night, doesn't let the scalp breathe properly. The poor breathing causes irritation of the scalp, oils building up, or the thinning of hair after some time. Your hair needs time to breathe and recover. This helps in keeping your scalp healthy while sleeping without the wig if you are wearing it most of the day.
Comfort And Sleeping Quality: Wearing a wig to bed can be uncomfortable. Most wigs are attached with either clips, combs, or elastic bands that at times can be painful and sometimes even cause headaches when sleeping. Taking it off means you can sleep freer and more comfortably, without concern about the damage to the wig or waking up with marks from the securing mechanisms of the wig.
Other Sleeping Options: You can also choose to cover the head with satin or silk scarves and bonnets in order to wrap up the natural hair or even a wig if you would rather not take it off when sleeping. They are fabrics that cause less friction, hence taking care of your hair and the wig.
In essence, when sleeping, it is always advisable to take your Afro wig off in order not to further damage either the wig or your scalp for your wig to last longer and serve you for a longer period of time, guaranteeing healthiness to your hair.