Hello, Im new to this site as well. I let the perm in my hair grow out about 3-4 months then CHOP! Went from Hair a little longer than my shoulder to the short do! I was so afraid of my how my hair would react. BUT my stylist deep conditioned and my curls emerged! I love my natural curls I haven't seen them since I was 6. Good Luck hang in there.
I don't know if there is any set amount of time. I personally just made the decision and went with it
but I did let me hair grow out about 4 mnths with no perm.