I only want to give a couple first hand experiences,
not intending to piss anybody off by any means,
just sort of food for thought type deal.

I knew someone years ago who didn't believe in
spaying, and never had an oops litter but the dog
had many, many nesting behavior episodes and it
was pretty sad to see. I seriously doubt that dog was
'happy' during those times.

My first gsd was spayed before her first heat. She
developed incontinence at about 7 years old, and
was very easily treated for that until her death at
14 years 3 months.

Current gsd is adopted but I was able to talk to the
original breeder. She was a later spay (after a couple
of heats) and at just turned 10 years old, no incontinence.
Should I add 'yet' to that? Okay, I will. But so far, so good.