Look beneath the colour
Flaking, powdery surfaces and staining are reasons to assess the existing finish, not simply cover it. Identify loose material and record defects before choosing the preparation. Recurrent moisture or movement may need separate investigation.
Protect what remains
Agree how floors, furniture, fittings and adjacent rooms will be protected. Record whether hardware is removed or masked and how access will be maintained. The protection plan belongs in the quotation alongside the painting.
Follow the chosen system
Preparation, primer and finishing coats should be considered together using the selected product instructions. Allow for the required drying conditions. If work exposes a different substrate or further damage, discuss the change before continuing.