Remathilis
Legend
I go by core books. That is, can you play the game without any further booksI do the following:
0e: OD&D
1e: 1e AD&D
1.5e: 1e AD&D post Unearthed Arcana
2e: 2e AD&D
2.5e: Skills and powers
3e: As it says.
3.5e: As it says
4e: As it says.
4.5e: 4e post Essentials
5e: As it says.
6e: 2024. I can see the argument for this being the half-edition, but its been 10 years since the release of 5e and this feels more like a major revision along the lines of the 2e revision where, things where things looked largely compatible and could be used interchangeably but there were major shifts in tone and minor across the board changes that made it a new game. It doesn't feel like the 3.5 release which felt more like errata. This is more like, "We want to get rid of demons and devils because we don't feel they are good for the brand, and paladins never should have been a thing anyway."
BECMI I see as an entirely separate and now abandoned branch of development.
1: OD&D LBB
2: Basic Set (Holmes/Moldvay/Metzer) + RC (Allison)
3: Advanced D&D PHB/DMG/MM
4: AD&D 2nd edition PHB/DMG/MC
5: D&D 3e PHB/DMG/MM
6: D&D 3.5 PHB/DMG/MM
7: D&D 4e PHB 1/DMG 1/MM 1
8: D&D Essentials HoFR/FK /RC /DMK /MV
9: D&D 2014 PHB/DMG/MM
10: D&D 2024 PHB/DMG/MM
Using those core books, you can play a complete game of D&D and it will play differently than the ones before and after it. Some are more compatible with the previous one than others are.
But I reject that 2024 is any more different than Essentials or 3.5.