A big one in southeast Florida is the # of parking spaces. A SFR (single family residence) by codes here usually has to have two parking spaces. The zoning code says what that size has to-be, there are variations. Common ones are 10' X 20', 9' X 19', 9' X 18' and there may be others. When homes were built in the 1950's and '60's, it was common in higher-density (smaller lots) zoning districts to have a single-car garage, and a single-car driveway. Parking on the swale or on the street in the right-of-way does not count towards providing required parking.
Enclose your carport, or convert your garage to living space, and you just eliminated one of your required parking spaces. If you only had a single-car driveway, you are now in-violation of minimum number of parking spaces required. Front yard setbacks are often 25 ft., so a single-car width driveway only has parking for one car. To be allowed to convert your garage to living space, you would also have to supply a plot plan/site plan showing another driveway parking space, sized to meet code. There are limitations on the size of curb-cuts for driveways, where they enter the roadway right-of-way.
It's easy to spot illegal conversions of garages or carport enclosures to living space, they only have a single-car driveway, and no carport or garage. Also, some types of driveways previously-allowed, like concrete two-track driveways for a single auto, gravel driveways, even asphalt driveways (where zoning now requires concrete or paver driveways) cannot be duplicated to provide the missing parking space.