Why doesn't Ash uses any of the Pokemon he caught in previous regions, apart from Pikachu? We only seem him use Charizard in Best Wishes and a few examples in Diamond & Pearl (only so far though because XY&Z haven't finished). I get how he wants to start fresh with each new region and use new Pokemon to beat the league (to make it more adventurous), but is there a specific reason for why he doesn't use them?
maybe laziness? if the games are anything to go by you have to go to a Pokemon Center, access the PC, access Bill's PC, put away one of your pokemon, go through the list of Pokemon in one box and realize you on the wrong one, change boxes and scan though that and repeat until you find the pokemon and go though the prompts to withdraw it.– Memor-XJul 21, 2016 at 12:03
10Because they need to introduce more pokemon to the series. If they keep showing the same pokemon, new pokemon would have less time to shine. Gotta catch 'em all.– 絢瀬絵里Jul 21, 2016 at 12:29
1@AyaseEri but new pokemons get the whole entire series/season(not quite familiar with how western countries do it) and they can maybe drop in a few of his old ones while battling the league which isn't taking up that much time, only a few episodes out of the one hundred to two hundred episodes per series– DragonJul 21, 2016 at 13:02
It's a rather simple marketing thing IMHO. I think that Ayase is correct. Yes it wouldn't be "hard" to have a throwback battle or two but the main point of the show is to supplement the game and give a more common view of all the new pokemon and attributes that players can take into play. So having throwbacks would be kind of against that. But I agree it would be very VERY cool. Imagine a battle royale with Charizard and every other fire dragon. It'd be phenomenal.– CallatJul 21, 2016 at 15:35
He used few more pokemon again, Snorlax , Taurus etc.– Ankit SharmaJul 25, 2016 at 13:10
From S05E275 ("Gotta Catch Ya Later!", second to last episode of Master Quest)
Ash: Professor! I've decided to start a new journey too, and only take Pikachu with me. I want it to be just like the first time I left Pallet Town."
Tracy: And you can count on me to take care of your Pokemon for you!
Ash: Really? Thanks a lot, Tracy.
Ash wants to experience the thrill of discovering the wonderful world of Pokemon all over again- a feeling he knows he won't experience if he only relies on his old Pokemon. He remembers how much he loved the experience of being introduced to a whole new realm, and how he had to work at leveling his Pokemon and growing with them to be able to eventually win the Orange League Championship. He decides to leave his Pokemon so he is forced to level native Pokemon, knowing he will grow as a person during this process. He leaves his Pokemon at Professor Oak's Laboratory because he knows they'll be well taken care of.
Throughout the Pokemon series, Ash only ever brings Pikachu with him to each new region, as Pikachu is his best friend and they are inseparable. The are two execptions to this rule: the Johto region, due to behind-the-scenes expectations (Pokemon was originally only going to have Gen I and Gen II), and Diamond & Pearl, where Aipom sneaked aboard the boat Ash took to the Sinnoh region.
From producers point of view, Ash using new Pokémon means that those Pokemon got time to shine. Sure they can have Ash use his old pokemon, but there are 2 problem with this. First is there will be less time for new pokemon to show their skills which translates to less time for them to attract people to buy their merchandise. Second is that if the old pokemon lose to the new pokemon, old fans would get upset.This was the case with Kamen Rider tokusatsu series where fans of Kamen Rider Kabuto would get upset at Kamen Rider Decade (the character and the series) due to Kabuto losing to Decade.
From Ash's point of view, he collects the pokemon. In battle there is always the risk of his pokemon getting injured or worse killed. Sure he can just go back to the previous area to catch it again. But this will cost money and time. Using new pokemon that live in the region he is in means that supposed that the pokemon got killed in combat he can capture another with less time and money spent.
I think there is a slight problem with this answer, but I will need to check with another question. Jul 25, 2016 at 20:11
1thanks for answering but with the buying the merchandise problem, all they had to do was do something special with the new pokemon. a great example is greninja, it is voted the number 1 pokemon in Japan due to Ash-Greninja so that problem's solved. and i see where you're coming from with Ash's point of view but Ash isn't that kind of person, he doesn't collect pokemon, he want to meet them. he only catches the pokemon that are willing to go with him (with some exceptions). from our point of view and a player of the games' point of view but personally as a Fan of Ash, i can't agree with you.– DragonJul 26, 2016 at 12:01