Since it's woodcutting.. don't 24/7. People will try to talk to you and will report you when you don't respond.
Maybe a max of 8 hours a day, 7 days a week? Although if it's an account you don't really care about (a fresh skiller you just made) feel free to 24/7. There's many accounts that can make 99 going 24/7 without getting a ban.
How important is the account to you?