Todd, we don't allow visitors, even friends or family, when we have puppies.
And, actually, we have become quite reclusive...people know that we have dogs and, frankly, most visitors would rather not be around that many barkers...so when people who know (and love) us want to visit, we either stay outside (on the lawn overlooking our beautiful property...sitting comfortably in the outdoor furniture
) or we meet them at a restaurant.
If someone does come over, we limit the area they go into (by keeping doors shut...they don't try to go into a closed door area) or we ask them to put on paper booties! LOL
Still, there is always a risk...even when Dave and I go out and come home...but we are very aware of WHERE we go...for instance, when we go to the vet, we are cautious about our shoes and clothing...and we NEVER go to places like shelters or dog parks without taking extreme caution...even when we don't have puppies at home...as you know, the germs will last.
I rarely let strangers visit...I just won't answer the door if I don't know someone is coming. I know that sounds odd...but I keep my dogs safer that way.
Oh, and we can always disinfect...we don't have carpeting so disinfecting is easier.