Keeping new animals in quarantine and away from your existing collection is really very essential. I don't know how well it would go over in a pet store to give that advice to a customer but that is the accepted practice among knowledgeable keepers. Every once in awhile someone who doesn't quarantine brings home a sick animal and infects their collection and at a minimum incurs huge vet bills and at the worst loses their whole collection. About a year ago, one woman who was attempting to become a serious breeder had to destroy her whole collection which included some very nice snakes. She should have known better and it was a terrible occurrence that can now only serve as a cautionary lesson to others.