I can only tell you my experience with Sophie. For the first five years we had her alone she was very reactive on leash. So much so that she was known to leap out of leash or harness to go after another dog barking. But off leash she was a different dog. She would keep to herself but sometimes would join other dogs in play. She particularly preferred dog friends that were smaller. Early this year she was on leash and attacked a puppy...not fatally but bloody enough to realize she can never be safely around other dogs again.
I considered a muzzle. We walk during off hours so we can walk alone. But there is always the risk of someone else walking their dog. Because of my job I've gained a lot of arm strength over the years. I feel confident that if Sophie saw another dog now, knowing what I know I could safely pull her down and restrain her. That's something you have to weigh with your own abilities.

Lovemybull, you speak very true words there. We always need to evaluate how strong we are in comparison with our dogs before we consider whether a muzzle is truly needed, or TBH whether we even need certain breeds.

I'm extremely strong and built very sturdily and can easily handle any dog I'd own, but because kids and other dogs often enter my space too quickly for me to react, I opt for the muzzle on Jadey anyway. I can easily pull her back if needed, but cannot stop an approaching or charging dog if he does not want to stop.