Pokémon has the tradition to bring out two versions of a main game simultaneously. Those versions always have slight differences, such as the available Legendary Pokémon and different Fossil Pokémon. Do you tend to stick to one version of the game, or do you always buy both? Why?
Typically I'll only get one of the two. I don't usually have enough money for both and these days with the ease of trading and GTS and all that it hasn't been too difficult to get what I missed. This generation I might get Moon after the holidays depending on what kinds of gift cards and gift money I'll possibly get, we'll see.
I get one, but I'll end up playing both at some point either because I bought one because SERIAL CODES/FIGURINES or because my brother got tired of his game.
I get both, mainly because I have two 3ds's and I can trade myself if I do happen to play the other game, and plus that means I get double the event Pokémon!
Typically I only buy one, I have swapped from a physical to a digital copy before a few times (both xy and oras). I don't have the money to buy both, but it would be a burden for me, only having one 3DS.
I usually only got one and then the third, because my brother or sister would get the second. But now with Sun and Moon, I decided to get both because I was running into troubles with the 6th gen. Even if I could transfer my Pokémon with Bank, the fact remained that I would lose all progress on my AS and I didn't like that. Seeing as I treated it as my main game and my X game as my challenge game (The sucky story made it hard to keep it up), I felt that getting both this gen would be the better move.
I always get the pair and if there's a third, the third. I like to use the second for trading with myself when needed and any experimentation I might not want to do on my main game. I also find that in the case of something like X and Y, I completed my living dex on X and thus had almost no room at all left in the physical cartridge to put things like my growing shiny collection, and although bank is an option, a part of me certainly didn't like the idea of my valuable Pokémon sitting remotely somewhere XD so I use them for reliable storage as well.
Generation 1 I have all 3 games- Red, Blue, and Yellow.. but beyond that I have one of the two, then the third version Silver (I had Gold, but the battery died on it and I got rid of it before learning that I could replace it), Crystal, Sapphire, Emerald, FireRed (there wasn't a third version), Pearl, Platinum, SoulSilver (again no third version), Black, Black 2, X, Alpha Sapphire, Moon why? cause I can't afford more than one game, and it's usually too similar for me to rationalize wanting to get both. instead I look at the exclusives and choose based on them. Originally I was going to get White, then I learned of the Gothita line being only in Black so I went with it.
I always end up getting both. I've done that since Diamond and Pearl. I like to have one game to keep all of my good stuff on and another game to replay and do nuzlockes and stuff.