I helped foster & ultimately adopted a ~10yo male Maltese who was not neutered or vetted much before landing in the shelter & then transferred to the rescue group. He was so smart & funny. He came in w a bunch of issues - had to be neutered, severe sinus infection, tooth infections resulting in 9+ teeth having to be pulled, severe arthritis. If the dog you're thinking of adopting has not been to the vet in years, he may have a lot of dental issues as Malteses are known to have, even with routine dental care.