I run around to lessons and meetings with my macs alot and must admit since the last battery calibration I had was when I bought the mac and when I bought the spare battery. Its a must especially when you are in long meetings and out of range from a power socket.
Changing batteries is painless, just take out the battery and put the new one in. Mac restores all your open apps after an initial wait.
With 2 batteries, coconut battery will be good for me to monitor how I should rotate them to prolong their life span.
Good to see the battery still healthy.