Buying the comprehensive package when you needed a refraction
If you are young, healthy and simply need updated glasses, the full screening tier is usually money spent on reassurance rather than need. Match scope to situation: screening earns its price for over-60s, diabetics, and anyone with a glaucoma family history — not for every routine prescription top-up.
Waiting for a child to complain before testing
Children rarely report blurry vision because they assume everyone sees the way they do; the signals are squinting, sitting close to screens, and slipping schoolwork. By the time a child complains, myopia may have progressed for a year or more. An annual test through the school years is cheap insurance against exactly this.
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.