Hardware versus labour: the split your quote should always show
The most common way people overpay is by accepting a single bundled number. A quote that says a smart lock 'supplied and installed' for one lump sum hides the markup on the hardware, which in the UAE can be substantial — the same lock model can cost noticeably more through an installer's supply price than it would if you bought it yourself online or from an electronics retailer in Dubai or Sharjah.
Ask every vendor to split the quote into device cost and installation labour. Install-only pricing for most single devices — a lock, a doorbell, a thermostat — typically sits in the AED 200–450 band. If the bundled quote is far above device retail plus that band, you are paying a convenience premium and should at least know you are paying it. Sometimes the premium is worth it: the installer warranties the whole job, sources a model they know works with UAE door profiles and AC systems, and will not blame your hardware if something fails.