For my own personal dogs?
Ideal: 2
Max: 2-3
I'd love to have the dogs spaced out so that one is middle aged and one a pup at the same time. (And then it would be senior and middle aged. When the senior passes, time to get a pup again.) Lucky for me, this will hopefully be how the timing works out for my NextDog. I'd like to add one when Abrams is in the 4-6 range. (Well, I want one NOW, but realistically, it is better to wait.)
For household dogs? (Aka, DH's dogs included.)
Ideal: 3-4 total household dogs
Max: 5-6
Although this totally depends on the size of our house/property and the size of the dogs. Where we are right now, there is no way we could have more than one more dog, and it would need to be no bigger than 60 pounds (ideally 50lbs or less), or we just wouldn't have the room!
If we have tons of acerage/a large house? I could definitely see having a few outdoor "barn dogs" and then a few "house dogs" as well.