Okay so i have a couple of questions about Maintenance costs and the replacement of aircraft
1)First does anyone know at what rate the maintenance costs of each individual aircraft increases?
I know the longer you have it the more it increases but at what rate
2)And is there a specific point at which it's becomes un-affordable to keep an aircraft and it should be replaced?
Some people say they replace their aircraft once they reach 7 or 10 years old, but is that just to keep the fleet young? or is this when the aircraft become overly costly to operate?