You can get more from other trade-in services or by selling it directly to a buyer, but I find Apple's trade-in hassle and stress free. You get two weeks after buying the new watch before having to turn in the old one, so you can set up the new watch and make sure everything is working as expected before giving up the old watch. You can take the old watch to an Apple Store, and an Apple Store employee inspects the watch in front of you and confirms its condition, then tells you the trade-in value.From what I’ve read, Apple doesn’t offer much for Apple Watch trade ins?
Other trade-in services I've looked at, you have to mail in your device, and they inspect your device and tell you the final trade-in value after they receive it. There's always the chance that their evaluation doesn't meet your expectation. So I prefer trading in to Apple.
I've gotten around $120 for every watch I've traded in. I forget exactly how much you get for a year-old watch, but I think it's less than $200. That price makes me feel like I'm getting less than I could for a year-old device. The prices for older watches make me feel like it's not worth the bother. But the price I get for a two-year old watch hits the sweet spot. It gives me a substantial discount toward getting a new watch, while letting me feel like I got my money's worth out of the old one.