I decided to try keeping it plugged in ALL the time. If I unplug it for any reason I try to allow it to discharge a fair bit.
I do that, not because I'm particularly clever, it just seems easier, i.e. when in doubt, do nowt, and so far my battery has been going for about year. As it is plugged in, there doesn't seem to be much point in changing from Sleep to Hibernate - to me at least.
If I could be bothered I would take the battery out and use it without the battery only installing the battery when I wanted to use it.
I used to do that, then was chastised by my Man Wot Does on the grounds that when we get one of our very frequent power cuts in rural NZ, I would lose all that I was working on at the time, whereas currently when the mains current fails the battery current keeps things going, I then disconnect to avoid some 500 volts going through the system - once lost a fax machine like that. ( I know, I could use one of those controller thingies, but not on the whole house, so I just go around switching things off, except in the middle of the night, when I subsequently wake up to lots of blinking digits and little lights around the place.)
Point is, like many things in Life, ask 2 people and get 5 answers, and having tried many battery tricks, keeping it permanently plugged in seems to be working OK.
For now !