Regarding late castration, a short story:
Our local rescue had a 9 yr old Treeing Walker hound, a huge fat sweet super doggy-dog. He'd gone place to place, folks couldn't walk him, always nose to the ground, peeing on every bush. Placed with experienced owners, trainers. He'd mark in the house too. Jumped out of 6 foot privacy fences. 6 foot chain link, always on the move.
They asked me, "what if we castrate this dog?" -- I said absolutely not, ridiculous, possibly cruel at that age, will make no change in his entrenched behaviors.
Well, someone else cut the dog. He got a home, 12 yrs old, sleeps on the couch, cats laying on him in winter.He used to eat cats. He's never run off again. He doesn't mark.
Maybe he just got older or a better handler but it seemed to the rescue folks that the castration made a huge change in this particular case.

Friend of mine adopted a 4 month old puppy (obviously intact). He's not a super trainer but he did well with this puppy. Dog had manners, got well socialized, walked nice on a leash, did tricks, etc.

When the dog hit about a year things started to change. While the training was still enforced he started trying to mark CONSTANTLY on walks, he was corrected every time he did so, as long as he was under command he was fine but there was no "break". In pet stores he had to be heeling the entire time or he'd be urine licking or thinking about marking (never managed to, his owner was always watching him). Outside in his kennel he'd be urine licking or looking to mark, you could just have him off leash relaxing unless he was under hard command (down stay, etc). This went on until the dog was a bit over two when he asked me what the hell he was doing wrong.

I suggested a vet visit and bloodwork to see if anything was off, it wasn't, couple hundred dollars later and he was found to be perfectly "normal" obnoxious companion dog with excellent OB and manners who got no chance to be outside of command. This was not a "dominant" dog either.

I suggested he neuter him. At this point he was just looking for SOMETHING to try, and the dog wasn't ever going to be bred anyway, and he was old enough not have any major health ramifications. He did it....

The change hit around the 2 week mark, same dog, same personality, no urine licking, no obsessive marking, no food refusal if a female dog came around. I remember the first time we went to the trails after the surgery, my friend gave his dog the "free" command and the dog ran around! He sniffed a few trees, peed twice, then played. He chased squirrels, he tracked small ground animals, he played with Ryuk instead of sitting there licking his sheath, his recall (that was never really off) was AMAZING. For the first time this dog had fun outside command and was able to actually function.

The dog's about 3.5 now, owner's happy, dog's happy, neutering did made a HUGE difference here.

Well, if this thread is hijacked...:-)

I never had a male, and I have let this first mark in the yard, and on walks, unless I tell him not to do it. He will urine lick, but he is not obsessed about it wherever we are. He plays great, and we walk off leash every winter in the woods and he has a great time. I almost never see him lick his sheath, sometimes I wish he would every now and then so as not to leave little willy marks everywhere on the floor.

AT 2 years and 9 months, this would probably be a great time to find out that I am making a big mistake.

I've had many dogs in my lifetime. Never less then 2-3 at a time in the past 50 yrs. Multiple intact males with intact females. Multiple intact males together mostly. I've had two males that were cut and two females that were spayed. None for temperament or behavioral issues.
My two present male, intact, working line GSDs are outside together 24/7 but both spent the first 6-8 month in the house learning manners. They both do there duty in one part of my very small back yard. Most ALL the other dogs were house dogs.
All my house dogs have had free run of the house after 6-8 months old, excluding females in season of course. No crates at night. Even with multiple males and a female in season I've never had an issue with any dog peeing in the house other then a very old, incontinent Norwich terrier. It's a training/leadership issue. JMHO of course!

Come to think of it now... He also can't just play with Zuki and is obsessed with smelling her. I would love to get past this problem but don't know... I would rather keep him intact. I still think I could fix it I just can't totally commit to it completely right now.

Elizabeth you are right in wanting to keep him intact --- the testicles are not "designed to be removed", likely contribute to the dog's overall wellness in ways we don't even know. EG I wonder if my dog, castrated young, is getting overheated more easily because he is neutered. My old body (now without estrogen) sure does overheat
more easily than it used to.

Elizabeth, is there any way you can put him in a no-fail situation while you are not with him?