I kept both the 600PF and the 180-600 along with the 100-400. My 2 lens/2 body outing kit is the prime and shorter zoom…the longer zoom is for a lighter load if I only want to carry one or if it's a longer hike where weight becomes important. If I had to choose I would lose the long zoom before the 600PF hands down…and may end up selling the longer zoom depending on how much it gets used. I also had and sold the 70-200 because it never got used…too short for wildlife and on the few occasions it was used f2.8 wasn't important. But yeah…use case is important.Your other lenses - I'd argue you can ditch the 200-600, or the 600 prime. But that's just me, and I'd likely keep the 200-600. Everyone should have a 24-70 or similar. And the 20, 50, and 90 macro are keepers (again for me). You could probably also sell the 14 or 20, but personally I love a good 20 prime.