Washing or detailing on sun-heated panels
Products behave differently at 70 degrees: soap flash-dries into streaks, polish gums up, coatings cure before they level, and cold water on hot glass and paint adds thermal shock. Morning slots, shade or basement parking are not comfort preferences — they change the quality of the result.
Judging vendors on the handover shine
Fresh dressing and a wet-look finish flatter any job for 48 hours. The real quality indicators are process questions asked before booking — wash sequence, decontamination steps, depth-gauge use — and how the paint looks under an inspection lamp at handover. Comparing two or three scoped quotes rather than one glossy promise is the cheapest quality control available.
Polishing too often
Every machine polish removes clearcoat, and clearcoat is a finite budget of roughly 40–60 microns for the car's whole life. Cars that get 'a quick buff' at every service end up with thin, UV-vulnerable paint within a few years. Protect more, polish less: correction should be an occasional reset, not routine maintenance.