I started my young life as a yacht painter in my grandfather's boat shop at 12 and have been painting and house building all my life. We built boats of wood because we had nothing better, we built homes of wood because we had nothing better. I grew up putting wood siding (cedar, redwood) on houses, it was the best we had. Now I tell people use cement siding, paint it once every thirty years if it needs it or not. https://youtube.com/watch?feature=player_embedded&v=b6_WEt9k_Hw
Thorough preparation is essential to ensure a good finish. Contractors might have to fill cracks or holes and remove old paint if it is badly worn, peeling or flaking. They remove all paint and apply a suitable primer to the bare surface. If the existing paint is in reasonable condition, they clean it and rub it with abrasive material to provide a key for the new paint. On new surfaces, such as bare wood or fresh plaster, they apply a suitable seal, followed by a primer coat.
If you paint over dirty, oily surfaces, the paint will easily chip or peel off. So before painting, clean grimy areas with a deglosser or heavy-duty cleaner intended for prepaint cleaning. They work well to clean painted, varnished or enameled surfaces to improve the adhesion of the new paint. They’re ideal for cleaning greasy or oily areas like kitchen and bathroom walls and removing hand marks around light switches and doorknobs.
