Booking one small job at a time
Every visit carries the call-out minimum, so three single-job bookings can cost more than one half-day visit that clears ten jobs. Keep a running list on your phone and book when it reaches three or four items. Vendors also quote batched work more competitively because their travel time is spread across more billable tasks.
Putting a full-motion TV arm into bare plasterboard
An articulating arm multiplies the TV's weight into leverage at a few fixing points, and plastic plugs in gypsum cannot resist it. The mount holds during the demo and fails weeks later. Insist on metal studs, a backing board, or a different wall.
Skipping the building permit and losing the slot
In permit-controlled towers, a technician stopped at security is a wasted visit that you may still be charged for. Five minutes with building management before booking, asking about NOCs, service-lift rules and drilling hours, protects both your slot and your deposit with the building.