If your dog isn't red rocket, humping everything in sight constantly, showing aggression, looks like he's losing his mind when you take him out you can wait. They can and do run away never to be seen again if they get a whiff in the air of female in heat. That's the danger because he will matter how diligent you are. If you notice red rocket far more often then it's time. There are hump toys but that's only going to get you so far. One day he will bust out to go find some. Plus it's painful to have yearnings unfulfilled huh.