I know it has become a staple of Star Wars history but I never thought that there were actual "Red" or "Gold" squadrons when I originally watched the movie as a kid. I thought they were simply the squadrons' callsigns. Same with "Home One", which was clearly a callsign. Seriously, who would name a battleship and a fleet flagship at that "Home One"!? At least the X-Wing series tried to fix it and call it Independence but that was later retconned. Meh.

Whatever, my point is why should things be taken so literally? Real pilots in wartime flew a number of planes. Whether their "mount" was lost to ground fire, shot down, mechanical wear or engine/structural failure. Luke's "Red 5" X-Wing was just a random beat down X-Wing* that was likely replaced with other random not so worn X-Wings as the war progressed.

* don't get me started about how stupid the entire X-Wings "are super secret top of the line stolen fighters" thing is. At best they should have been the previous generation (Clone Wars/pre-Civil War years) top of te line fighters, like late 1980s Su-27s or F-15s.

Even the supposedly inferior TIEs are clearly faster in the Death Star trench run and look newer/more modern. ;)