As Express10 rightfully said, older hobbies can take you on a trip down memory lane which - in most of mine - was occupied by the nationalist socialist party, they were that bad. It also depends on the hobby. I used to collect "Warhammer" miniatures for a game I never played; you built them, painted them and sent them into battle through a very advanced military game. It was expensive buying the rule book, the specific army's rule book, the paint, the glue, the model cutters, the terrain, the miniatures themselves and various other things - you could spend a fortune just "getting started!". That's not the best hobby to go to. A good hobby I'd like to go back to is writing fiction, one that took up any time I had, both free and schooltime. I loved writing, still do, but I can't really get in the mood any more. I liked the characters I created, the monsters, the scenarios, the backstories, the settings and a great deal of other peripherals in my book's universe, so going back to old hobbies isn't inherently a bad thing.
New hobbies can give you some new perspective, seeing it as someone who is active rather than watching someone else do it over their shoulder. You can learn valuable life lessons from it, teach and encourage others with it and perhaps find far more entertainment and lasting appeal than any other hobby you might've indulged in.
My question is, why not do both if you can? If your hobby was originally collecting things, that could be something to do on the side of writing articles about those things you collect like I do with PS1 games on my YouTube channel. I like to combine my hobbies such as gaming and writing to become a journalist, or collecting models and drawing inspiration from them for a new idea of novel.
Neither is better, and both are perfect in their own right. Either way, an old hobby was once new at some point; in a few years, it might feel that way all over again.