Laptop Battery Health

I've been trying to find out the best way to keep my battery healthy - the last laptop I had ended up with about 30mins of charge by the end (mostly due to a dodgy charger)!

I've read that it is best to avoid running the battery down to nothing and charging all the way back up, and also to remove the battery when running on AC power.

However, removing the battery every time I have the laptop connected to the charger is a pain, and if I want to go to a different room a have to reattach it. So if I were to leave the battery in would it be better to either:

a) Leave charger in keeping battery at 100%

or

b) When the battery reaches 100%, remove charger and run down to, say, 25%?

Sorry for the long-winded question, I just want to avoid a useless laptop like my last one!

Thanks in advance,

Jonny