Some people collect postage stamps and pay thousands of dollars for one that you can't even send a letter with.
Others (Like my missus) have horses and pay a small fortune for each animal each year.
Others like to drink a lot every night.
We just like to collect planes

Well that's my justification anyway (Just don't tell the missus it's flawed - she'll breed another horse or buy some more tack and that could be one less plane for me).

There's never enough planes and certainly never enough servos or engines.