Drywall problems split into two paths: patch (cheap, fast, same-day) or section replacement (more expensive, slower, but the only correct fix when the wall is compromised). Three rules decide which one your job needs — the 4-inch rule, the moisture rule, and the texture rule. Get them right and you save hundreds of dollars; get them wrong and you pay twice.
The 4-inch rule
Holes under 4 inches in any direction get a patch — usually a mesh-tape patch with hot mud, sanded smooth, texture-matched, primed and painted. This is the standard doorknob-hole repair, the over-driven anchor, the pet damage. Total cost in LA: $145–$285 with paint included, finished same-day.
Holes between 4 and 12 inches get a California patch (a piece of new drywall set into the existing wall with the paper layer used as the bond) or a backer-board patch with mesh tape. Cost: $200–$400.
Holes over 12 inches usually mean the patch will look obvious no matter how skilled the technician is — small irregularities show on a large repair. The right fix is to cut the section square back to the studs and replace the drywall outright. Cost: $400–$1,500 depending on size and ceiling vs. wall.
The moisture rule (the 48-hour line)
Drywall that's been wet for less than 48 hours and is now dry is usually salvageable with a stain-blocking primer and a paint touch-up. The gypsum core hasn't broken down structurally and mold colonies haven't established.
Drywall that's been wet for more than 48 hours is structurally compromised and can grow mold even after it dries. The right fix is to cut back to dry, undamaged material, treat the framing if needed, and patch with new drywall. There is no shortcut to this — painting over wet drywall just delays the failure and grows mold inside the wall.
The texture rule
If your home has a hard-to-match texture — heavy skip-trowel, custom Spanish lace, an unusual hand-troweled finish — sometimes a smaller area cut-and-replace is cheaper than trying to patch into an unmatched texture. The math: a $400 section replacement that looks invisible beats a $250 patch that looks obvious from across the room and bothers you for the next decade.
Most LA homes have orange peel (1950s–1990s), knockdown (1980s–2000s), smooth (modern remodels and 1920s plaster conversions), or skip-trowel (Spanish revival). The first three match cleanly; skip-trowel and Spanish lace sometimes don't.