Twelve years ago, his fletchinder is the only pokemon he keeps.
Pokemon are a lot of work and they deserve better than someone distracted by other things, Anderson knows, and, frankly? He's kind of tired of all the work maintaining them all is. And, "You've gotta have a fire type if you do any work in the forests, everyone knows that."
"What a practical boy you grew into," his mom says, and he beams.
"Been listening to your old man, huh?" his dad says, and he beams harder.
This is the part where in the stories he's grown up seeing on TV there's a nostalgic swell of music, he thinks back to all the good times he's had with them, and it's this huge deal, it's A Boy Becoming A Man And Putting Away Childish Things. They hug it out one last time, he gets just the hint of tears in his eyes but doesn't cry because he's too grown up for it now and this is the final proof of that, a badge even more important than any of the literal badges he got along the way.
But really, pokemon are just so much work. The teddiursa still gets into trouble if you take your eyes off him, if anything he gets into so much more trouble now that they're not battling all the time. He climbs on furniture and cabinets, even broke through the screen of one window. And even his well-behaved leafeon, the one who was so good from the very moment he got him, who he'd never expected difficulty from, is all antsy and alert these days. The leafeon's always jumping up and throwing himself into absolutely anything that looks like a task with entirely too much energy, to the point it's getting exhausting just thinking up stuff for the pokemon to exhaust himself on. He only got them and kept them because it's what you do, because he needed to prove he could handle himself in a fight and as a trainer.
And it wasn't awful, doing that, he's not saying he hated it or anything, just like it wasn't awful taking tests and doing homework to graduate from elementary school and move on to being a pokemon trainer. And just like that, he's still glad to be done with it all and able to move on to the next part of his life.
"I figured Flechinder's the best one I could have," he tells his parents. "Because it's part flying too. So it's not just good for dealing with a dangerous pokemon but if anything else goes wrong, or if I find somebody else in trouble, I'll be able to get help."
He loves the deep forest but he knows it can be dangerous. Indeed, that's part of what he loves so much about it, the challenge, the fact not everyone can handle it. You have to respect the forest. Other people, especially those who didn't grow up here, they could end up in real trouble because they don't know that.