Is it better to lay a ballpoint pen flat or upright when not using it?

Does gravity help the pen's ink stay at the tip? I want to get the most ink for my money. I got a Waterman pen set for Christmas and the refills cost $6.00.|||My experience is if you stand it with the tip down the ink leaks. If you stand it upside down the end of the pen dries out and won't write as well. I would go with the on it's side. What's the worse thing that could happen? I can't think of a thing. :)