Here's the deal from our POV.
DW and I have had dogs and cats nearly throughout our entire lives. When we went fulltime 15 years ago, it was with 3 cats who were acquired via the Humane Society. One was 1 y/o when she came to us, the other 2 as kittens 6-8 weeks old. All a bit older when we "left home". One died at age 10 and the other 2 last year at ages 17 and 18. All of them were FT troupers. They didn't know that a rolling home wasn't just the way it was supposed to be. They are sorely missed. I'm misty as I type this. BUT:
We decided not to have any more pets because we believe that at this point it would be more selfish by us and less beneficial to them. We are 64 and 60 respectively and have no family with whom we would entrust the care of them at the inevitable event of our demise. We simply believe that it is irresponsible to acquire a pet who is likely to outlive you.