I know that a lot of details would factor into this, but I am
wondering what bicycle enthusiasts consider when buying a new (or
used) bike?

Here's the problem: getting into riding a bike again, especially as an
adult, brings back all those great memories you had as a kid. It's fun, it's
liberating, it's just cool! So, you had a bike that brought you enjoyment
and you really, really liked riding it. So, one day, you think of riding it
to the store. You get there and the realization is....what do I do with my
new bike while I'm in the store? Where will I lock it up? Will it attract
thieves?

You then know you need a bike that's not too attractive to thieves but is
still reliable and relatively fun to ride: a "beater bike." But, it won't
satisfy your new-found need to just get out and have fun and ride
everywhere! Ergo, you need a better bike!

Yep, you'll eventually need two bikes! The "store" bike will be utilitarian
but it won't satisfy your need to fly....

Get the beater bike, the used mountain bike or used touring bike, first. As
you ride more and more, you'll see what I mean about getting the "better
bike" as well. Sigh. That's just the way it goes. But, a few months down the
line, you'll also know more about what you want in a bike. You'll have some
education that comes with experience in adult bikes. Dreaming about the
"better bike" is half the fun of riding the utility bike. And then when you
get the "better bike", you'll really be satisfied.

Pat in TX