Currently considering a move from New England (not Boston area) to Las Vegas. I thought I would never move out of the NE again but time has proven me wrong. In my 40s, I've finally learned to never say never.
Anyway, here are my top considerations in the move:
1. Lower housing and cost of living in Vegas than here.
2. Climate. I used to like the cold but I started becoming intolerant of it as I hit my late 30s. Now I no longer enjoy it. I was always a heat wimp, so I was shocked on my last visit to Vegas (I go about twice a year) to find I was actually liking the hot summer there better than the cold winter here. That's probably what planted the seed re: moving.
3. Allergies. My tree pollen allergies are getting progressively worse each spring. The last couple years I've been miserable for 4-6 solid weeks in April/May/June as things bloom. I'm also sensitive to mosquito/bug bites and there are a ton of them out here since we're basically in the woods. The humidity here in summer is awful as well.
4. My daughter (16) is a dancer and also wants to become a makeup artist. There are no job opportunities in those fields where we currently live. She would have to move anyway once she hit 18 to find a job. (She also hates the winter/snow.)
5. Three of my best friends live in/near Vegas. Then I have another set of good friends in LA and SoCal, also some in San Jose. I would get to see my friends again, more than once every 10 years. And I would get to actually socialize in person with my best friends more than twice a year.
6. We've had a horrible run of rotten luck the past couple years. I am talking major traumatic events. A fresh start in a new place couldn't hurt. We really should have moved when the bad luck began, but I thought rocking the boat in that way would make things worse. Instead, staying made things worse. Oops.
There are other reasons, but those are the biggest ones.