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.
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.
Judging the quote instead of the method
The cheapest quote often prices a different job: silicone over silicone, plugs instead of proper anchors, no anti-tip strap on the wardrobe. When quotes differ widely, ask each vendor how they will do the job. The one who mentions wall type, anchors and cure times without prompting is usually the one worth paying.