If possible, stick with the same buddy. You'll know each others air consumption, you'll know how to better communicate with them underwater, you'll probably also stick with each other better. If you don't have the luxury of having a consistent buddy, then if you get a chance to have a repeat buddy that you enjoyed diving with, certainly go with what you know. Otherwise, you never know what you might get. Always ask questions about their experience and skill and go over the lost buddy procedure with them to make sure they understand because that is one thing you don't want to miscommunicate on if something happens [of course, it doesn't help if you have one of those 'buddies' that just wander off...
