Every summer we get called to houses in Pasadena and Deer Park where an exterior paint job two or three years old is already lifting in sheets. The homeowner almost always assumes they were sold cheap paint. Occasionally that's true. Far more often, a perfectly good coating was applied to a surface that was never going to hold it.
Paint bonds to what it touches. If what it touches is chalky oxidised residue from the previous coat, or damp wood, or bare cedar with no primer, then the new coat is bonded to a layer that is itself letting go. It looks flawless on handover day and starts failing the first time the wall heats up, swells, and cools.
On the Gulf Coast three things make that worse. Humidity means siding holds moisture longer than a contractor's schedule wants to admit. Salt in the air near the bay works into every unsealed joint. And the sun here delivers more UV over a year than most of the country, which is hard on the resin holding any coating together.
The prep that actually prevents this isn't complicated, it's just slow. Wash the surface and let it dry properly. Scrape back everything that isn't firmly attached, which on an old house can mean most of a wall. Replace the boards that are soft or split rather than painting over them. Spot-prime every piece of bare wood the same day it's exposed. Renew the caulk at every joint where water can get behind the siding.
Then watch the weather, not the calendar. A coat applied to a wall that's still damp from morning humidity, or one that catches a four o'clock storm before it has skinned over, is compromised whatever it cost per gallon.
When you're comparing exterior quotes, the useful question isn't which paint brand is on the sheet. It's how many days the quote allows for prep, and whether repairs and priming are line items or vague assurances. A quote that's a third cheaper and finishes in half the time is telling you exactly which part it plans to skip.