This is where most of the labor — and most of the cost — goes. It’s also the part you can’t see once the job is finished, which is why it’s the first thing a low-ball estimate skips.

For an exterior job, prep means:

• Pressure washing the entire surface to remove chalk, mildew, and dirt
• Scraping every area where old paint is loose, cracking, or peeling
• Sanding the edges of scraped areas so they feather into the surrounding surface
• Replacing or repairing wood that’s gone soft — trim, fascia, siding boards
• Caulking gaps at trim, joints, and penetrations to seal out water
• Priming bare wood, patched areas, and any stained surfaces
• Masking windows, doors, lights, and landscaping

For an interior job:

• Patching holes and cracks in drywall, then sanding smooth
• Caulking where walls meet trim and where trim meets the floor
• Moving or covering furniture and protecting floors
• Priming new drywall, heavily patched areas, and drastic color changes
• Degreasing kitchen walls and cabinet surfaces before any coating goes on

When a painter gives you a low quote and says they’ll “knock it out in a day,” they’re almost certainly skipping most of this list. That’s fine until it isn’t — and when it fails, the surface usually has to be stripped back to bare before it can be repainted properly.