But I am betting 3 of 3 from my personal experience...
If you want to mess around with your new pistol, modifying/buying/installing parts, patterning the ejection over hundreds of rounds, that's certainly your prerogative. But I don't think you can claim you're doing it based on personal experience when you have none with the brand in question. And it's very unlikely to be a money saving strategy.
As far as "hearsay" goes, here's some just for fun.
I own 9 Glocks at the moment.
*** One of them doesn't work, it's a cutaway model. So the comments below are only applicable to 8 of them
Number of Glocks that I have owned that have needed new or modified extractors to be reliable: 0.
Number of Glocks that have needed new or modified ejectors: 0 (To be fair, Glock did come out with a new ejector for one of the pistols I own. The pistol was not malfunctioning, but I figured going with the new part couldn't hurt. So I called them and they sent me a new one at no charge. I installed it and it was reliable without any fitting/filing/bending required.)
Number of Glocks that needed new springs or adjustments to any part of the ejection/extraction system to be reliable out of the box: 0 (Again, to be fair, Glock did come out with a new recoil spring assembly for one of the pistols I own. The pistol was not malfunctioning, but again, I figured having the new part would be good. They sent me one at no charge upon request and it worked fine.)
Ammunition required for patterning ejection to achieve reliability: 0 rounds.
Amount of money spent on parts to achieve reliability: $0
Amount of filing/grinding/tuning/bending required to achieve reliability: None.
Of course, 8 isn't a huge sample size--certainly not a guarantee that all Glock owners will have the same experience I did.
***No, Glock is not the only brand I own. I own firearms from a number of makers--in fact, looking through my inventory I see that when I count up the pistols I own by brand, Glock doesn't top the list. I own more than 10 handguns by one other maker.