Aeroplanes are stripped of their paint and repainted typically every 4 years. Decals may be replaced more often and if the airline is bought by another the schedule is pushed up so every aircraft is uniform and identifiable as part of a fleet. There is a weight consideration, for example, for a 747, the paint weighs in at 1100 pounds.
The exercise puts a plane out of commission for 5 days or so, which is why Fischer’s Inspection Programme is used by many in the industry as it ensures a thorough and accurate paint application.
Gauges conform to ASTM D 7091, DIN ISO 2178, 2360, SSPC-PA2, IMO PSPC and others.