Hiring a Plastering Contractor

When can I paint over fresh plaster?
In general you should wait at least seven days or when the plaster has changed color from a dark brown to a light pink.
Do I have to remove the wallpaper or paint before the walls are plastered?
I have had a leak in my bath and the ceiling has sagged a little - do I need to have the ceiling totally replastered?
What do I have to do to prepare my room/work area before the plasterers arrive?
Do I need to remove the carpet in the areas where you are going to plaster?
Should I worry about asbestos fibers in my existing plaster?
How can I recognize if an area of plaster needs replacement?
When you tap it gently with your finger you get a small echoing or a loose clicking sound rather than a sharp solid sound. It may also bulge slightly and move inwards when pressed gently with finger.