We had Glory spayed when she was 2....primarily because we had Clarke, and he was intact. The first few heats were ok with keeping them seperate, but then Clarke started getting really frantic with the pacing, drooling, and not eating. I know some people board their dogs when the bitch is in heat; but I could never do that....have never boarded our dogs.
She is 6 1/2 and is not incontinent; but I had a female years ago, who leaked before we spayed her, and my vet told me it was the way she was built...and it was common in dobes...that the way the 'plumbing' is; urine tends to pool just inside, so when she sat down, there would be a small pool. He demonstrated touching her back there, and it did drip out. I ended up having her spayed at 3 years old, and she never got any worse than the way she was prior.
I neutered Falcon already because he was cryptorchid...and they convinced me he would develop cancer from it. I waited until he was 18 months though. Funny; they asked if I wanted to 'see' it when I picked him up, of course I did! My husband walked away as they brought out the testicles they removed...one real large, and the other the size of an almond

My husband couldn't handle it