When I first met my husband we were post graduate students together in the same town but after six months our new careers took us to different places, and it took almost two years of long-distance hassle before we were together again.
At that point, we moved in together, then bought a house together, then married pretty soon after that and have never been apart since.
So my view of whether living together is a good idea is colored a bit by that. I think it’s a good idea and much better than living over a hundred miles apart! I like the idea of living with someone before tying the knot so that you can see how you rub along together when you’re not on your best behavior. My view is that you never really know someone until you live with them.