Booking exterior work at the wrong end of the calendar
Every May, someone signs off a full villa exterior job just as surface temperatures leave the paint's application range. The result is a rushed, compromised finish or a job that stalls until October anyway. Exterior painting belongs between late October and early April; if you missed the window, wait rather than forcing it.
Accepting 'a room' without a definition
Per-room packages are common in the UAE, and 'one room' can mean walls only, or walls plus ceiling, doors, frames and skirting, depending on the vendor. The gap between those two definitions is hours of labour and litres of paint. Pin down exactly which surfaces the package covers before comparing prices.
Skipping primer on gypsum and patched walls
Gypsum board and fresh filler absorb paint at a different rate to the surrounding wall, so unprimed patches telegraph through the final coat as dull, blotchy shadows — brutally visible under cove lighting. A sealer coat costs little and is the difference between a flat, even ceiling and one you notice every night.