+1 mount the new tires yourself. Here's another tip I recently saw. When you mount tires, put the middle of the tire logo even with the stem. Then, when (if) you inflate the punctured tube to find the leak, you will know where to look on the tire to find the breach and be able to remove the shard of glass or sliver of metal or thorn or whatever. If you don't remove whatever caused the flat, a new tube won't last long.