Tire replacement quandary

I'm getting ready to sell my first bike. It's a well-used Trek 7200 (not fx) so the price will be low.

I put puncture resistant tires on the old bike. One tire has maybe 600 miles on it -- would it make sense to put that on my newer bike? I'd be swapping an older puncture-resistant tire for a newer regular tire. I'm not sure if that's a good move since I don't really know what sort of lifespan tires have.

If I don't swap out the tires, I probably would buy a puncture-resistant tire for the newer bike (at least for the rear wheel).

I have recently fallen in love with Schwalbe Marathons, esp. for winter riding.

If I am riding in an area with a lot of debris that can puncture the tires, I will go with slime tubes in the rear wheel. That is where most of the weight is so would be where the stuff would be more apt to be driven into the tire. 600 miles can be a lot or a little to a tire, depending on the tire and how/where it is ridden. Heck, I had road tires that were toast at 1000 miles as they were formulated for a nice grippy comfortable ride but got cut badly due to the soft rubber compounds.

So I would say to look at the tire, and if it is in good shape, you should put it on the back if you swap it.

I usually keep both tires the same though, as I rotate them as wear indicates. I just use that slime tube in back and choose tires that fit the use and road conditions.