Babying your battery, as Gymnut put it, is acceptable and all but how much battery life will you really save? If you ask
most MB/MBP (or any laptop) users they will tell you they leave it plugged in
most of the time and they are a-okay. Battery technologies have come a long, long way. Try powering a current laptop with an older battery lolz. You'd need a gasoline power generator. They're made to last and, unless defective, they do just that.
Edit: the site aquajet posted is interesting. Check:
http://www.batteryuniversity.com/partone-23.htm
Read the middle column about Li-ion. Pretty much says keep it plugged in