When people picture a paint job, they picture rollers on walls. In practice, the rolling is the quick part. Most of the time on a well-done interior job goes into getting the surfaces ready.
Start with repairs. Nail holes, dents, and hairline cracks need to be filled and sanded flush, or they'll show through the new color, especially in flat or eggshell finishes under side light. Larger drywall damage needs a proper patch, not just a heavy smear of spackle.
Next comes cleaning and caulking. Kitchens and bathrooms collect grease and residue that keep paint from bonding. Gaps where trim meets the wall should be caulked so the line between wall and trim looks crisp instead of shadowed.
Primer is the step people most often skip. Patched spots, stains, bare wood, and big color changes all need it. Without primer, patches flash through as dull spots and dark colors take extra coats to cover.
Finally, protect the room. Floors covered, furniture moved and wrapped, hardware removed or taped. When the prep is done right, the painting goes faster and the result lasts years longer.