The AC POWER section of the FAQ addresses this. You should run a while on battery every few days to keep it healthy. Just unplug while you work, then plug back in a few hours later.
No, the instruction is to cycle the battery at least monthly, not to calibrate it. The WHAT IS A CYCLE? section of the FAQ will explain how cycles work.
You don't need to calibrate your battery. Read the link I posted earlier. If it doesn't work when you click on it, keep trying. Apple is having problems with its site recently, so you have to retry Apple links several times before they work, but the link is good. Reset your browser, clearing your cache.
PRAM/NVRAM has nothing to do with battery/power/charging issues. Resetting it will not help. Only
resetting the SMC addresses such issues.
Some people repair, or recommend repairing permissions for situations where it isn't appropriate. Repairing permissions only addresses very specific issues. It is not a "cure all" or a general performance enhancer, and doesn't need to be done on a regular basis. It also doesn't address permissions problems with your files or 3rd party apps.
Five Mac maintenance myths
There are times when repairing permissions is appropriate. To do so, here are the instructions:
If repairing permissions results in error messages, some of these messages can be ignored and should be no cause for concern.
Yes, that's correct. It can be 50% or 30% or 80%.... doesn't matter, as long as you're giving the battery a reasonable amount of use.
Hope that helps!