This is always my question about max battery usage. I have historically used my MBP plugged in when at home and not taken a charger with me when out and about except when traveling. I'm using an older MBP, early 2011, and my battery completely died last year. I installed a new battery next week so I'm trying to make it last as long as possible. When I bought the new battery, I also upgraded from 4 gb to 8 gb RAM and got a SSD drive. This thing is smoking fast now with the SSD, I love it and want to make it last as long as possible!
There is no easy way to do this, because the inherent way laptops work harm lithium batteries, and no laptop Makers have ever given consumers all of the tools needed to further prolong life. Additionally, maximizing LiIon service life often means radical changes to personal usage habits that may be inconvenient or completely impractical.
Lithium batteries do NOT like being at full (surge) capacity for extended periods, and they DESPISE being at extremely low capacity for extended periods. Their native voltage is usually ideal for storage and periods when not being used, but this native voltage may only entail 1/3 of the energy of a full charge.
While we can change our own usage and set the computer to power off at a certain percentage to limit the "depth of the discharge", I do not know of any tool that could easily configure a laptop to only charge the battery to say, 40% of capacity, and then terminate the charge, and only continue to the full surge charge right before you use the battery. That would be inconvenient and require planning in advance (or living with always having a battery of only 40% capacity.)
Additionally, the fact that lithium batteries also DESPISE heat & the fact that computers produce a lot of heat is also a problem (especially as components become increasingly crammed closer and closer together.)
So, subsequently, other than ensuring the computer has adequate airflow and that one understands the basic principles of lithium cells, the most practical thing to do is usually to enjoy the battery and just replace it once its capacity deteriorates, in my opinion.
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries