my twist last a month, not so much cus they unravel but because of under growth, they get kinda squished from the durag i wear to bed and the fact that i need to wash my hair. For scalp if you oil your scalp on your wash day or d day after, your scalp should be fine, n obviously oil ur scalp through out d time u have twists in. (Tip: the first time i oil my scalp after washing it, i use a oil with a thick consistency -i use cantu's tea tree & jojoba oil- as this oil will normally last 1.5-2 weeks. After this time ill then use a more runny oil 2-3 a week)