that's why three and I think the fourth will leave our company after original developer left undocumented and hard to understand code (it's pretty complex and has tons of hacks to work on different OS'es), first year they learn what the hell is that code, how it works and they are not allowed to comment anything (I asked few times why we waste so much time for basic stuff, they said it is unnecessary...ok I guess). Now they hired original developer for tons of money just to consult newest developer and explain him code. Reasonable I guess.