In most regulated systems, yes, meters are mandatory for licensed taxis on standard trips, but three legitimate exceptions confuse visitors. Airport and station routes often run on official fixed fares or prepaid coupons instead of the meter, which is legal and usually posted on boards. Some cities license a separate tier of unmetered rural or shared taxis. And app-dispatched rides price upfront, overriding the meter lawfully.
Disputes usually start one of three ways: a driver claiming the meter is broken, a suspiciously fast-running meter, or a scenic route. For the broken-meter claim, the correct response is to take another cab before departing, or agree a firm total if you are already committed. For fast meters and long routes, follow the trip on your phone map and note the taxi's license number visibly; behavior often improves immediately.
Airport-specific tips: skip anyone soliciting inside the terminal, join the official rank or prepaid counter, and check whether legitimate surcharges apply, since airport fees, tolls, luggage, and night rates are often lawful additions that look like padding. The city's transport authority or tourist police handle complaints, and hotels will gladly tell you what any route should cost.