Concrete forms

[Fishboy]

I've spent the past two days digging, leveling, placing forms, and pouring concrete for a walkway. This is my first attempt at bender board, but it formed very nicely to a couple of turns. What I don't know, and need some advice with, is when should I remove the forms? I used your standard concrete that says it sets up in 24 hours. I don't want to find myself having to pry off boards that are stuck to the sides, so is there some rule-of-thumb for taking these boards off?

Aloha pumehana,
Brian and Mary
Lynnwood, WA\Discovery Harbour