Half Birthdays

At what age do you stop caring about the "half birthday". It's really not about the actual date of the half birthday as much as it is about adding the "and a half" on the end of your age. I guess when you're 4 that extra half year makes a big difference. Anyways, I am 27 and a half today. So for the 3 or so of you that read this you should buy me half a present.