do you keep multiple tanks of the same species and morph?
Absolutely. For a long, long time I kept "a little of this, a little of that". Variety is nice, but sometimes you just find out what you like best. Or, you find out what taxa or even localities do best for you, given where you're living and whatever opportunities or constraints are operating for or against you.
So, consequently, for about the last decade I've only kept one or two species. For the 2 species I have now (and for about the last 4 years) I am maintaining constantly about a dozen vivs for adults, and more-as-needed just for baby-raising. Those latter ones are much simpler & smaller tanks of course, and are super easy to set up or tear down as circumstances dictate. I just reserve an area of the herp room for this purpose, and avoid filling it with another couple of adult vivs. My room is very near carrying capacity, given the large vivs I prefer for my adults.
I really like the "replicates", as - if you're so inclined - you can tinker with how you accommodate a given taxon. And thereby you can learn quite a lot
about what makes them do fine, or do super, or - possibly - do poorly. You can watch growth rates and weight gain or loss, appetites, activity schedules and amounts, etc. I'm scientifically predisposed, so willingly fell victim to such dorkery.
From this approach I have learned to keep my animals a bit cooler than I used to think necessary, and to feed them a bit less often. Now, that is not a uniform prescription, it's what I learned from my approach, with the taxa I keep. Having a naturally-chilly basement herp room, with 1) a space heater to maintain the room-wide overnight low temp, and 2) individual-tank lighting to provide daytime highs on a per-viv basis, have been instrumental in executing this approach.
Hopefully some people can gain inspiration from this. Not every part of getting old sucks. Learning happens, if you let it. Ha ha ha.