Assuming the home test counts for your driving licence
Licence vision certificates must come from centres accredited by the licensing authority, which file results electronically — a standard home visit is not that. People pay AED 150–400 at home, then discover they still need the approved-centre test. Use the home visit as preparation, and ask about accreditation before booking if the licence is your whole reason.
Accepting a verbal prescription or a 'we'll make your glasses' promise
Without a complete written prescription including pupillary distance, you are captive to the tester's own glasses pricing. The written document is what makes the market work for you — any optical shop can fill it. No paper, no payment.
Skipping the licence check because the price was good
An unlicensed test is the most expensive kind: a wrong prescription means headaches and wasted glasses, and an unqualified tester can miss signs that needed a doctor. Verifying a DHA, DoH or MOHAP licence takes two minutes. Booking through a platform that verifies vendors first handles the initial filter, but asking directly costs nothing.