Bell ringer, you obviously dont pay the bills on a machine. Here are a few examples of how the big boys rip you off
Compressor wheels cost to make under £ 200 sold at over £ 2000
MD bearings, cost to make under $ 50 sold for $ 1400. Mesh filter infront of compressor $ 12500 ( for a fibreglass frame with some garden mesh over it !)
S300 strut, cost to make $ 55 sold for $ 1600
AW pressure switch made for Euros 2k sold for Euros 32K
Sa 341 clutch o/h cost for YU reg £ 7500 for an EASA ac £ £ 32k
That is why your maintenance bills are so frigging high