I bathe my dogs as needed, also. Chipper, my Yorkiee-poo needs bathing a lot mor than Tootsie, who is a short haired Blue Heeler cross. Chipper seems to have more skin irritation than Tootsie does, as well, so even though he is mostly inside the house, he still needs more bathing.
I think that anesthetics or pain meds should be used when needed, regardless of age.
My Pekinese mix was almost 10 when we had her spayed, and she had no problems with either the anesthesia, or the pain meds that were given to her afterward.
I do think that vaccination shots are given way more often than is needed, according to what most vets are saying , so I do not do that every year.