It depends, but usually after a certain number of cycles, there will be a larger maintenance check (D-check, see https://en.m.wikipedia.org/wiki/Aircraft_mainte

It depends, but usually after a certain number of cycles, there will be a larger maintenance check (D-check, see https://en.m.wikipedia.org/wiki/Aircraft_maintenance_checks https://en.m.wikipedia.org/wiki/Aircraft_maintenance_checks). This will include removing all paint and performing lots of testing for cracks. It's possible to extend the life of an aircraft as long as it is economically viable (by replacing parts and performing the necessary structural repairs).