West Tampa's block homes and duplexes typically put the water heater in a garage, an exterior closet or a utility room off the kitchen. That gives good access, and it also means the unit is often exposed to the heat and humidity of an unconditioned space.
Gas installations are common in this part of the city, so the burner, flue and combustion air get as much attention as the tank. A unit that lights and then shuts down intermittently is usually telling you something about venting or the flame sensor rather than about the water.
Duplexes add a wrinkle: one heater may serve two addresses, or each side may have its own. Confirming which unit feeds which taps avoids testing the wrong appliance and quoting work on a heater that is not the one at fault.
Duplexes in West Tampa sometimes share a single heater across two units, and the meter arrangement is not always obvious from outside. Confirming which unit serves which side before testing avoids the embarrassment of diagnosing a heater that has nothing to do with the complaint.