Laptop Batteries: I just take them out

For those of us that use their laptop as desktop replacements, should we leave the laptop plugged-in or should we pull the plug?

My battery life has been very poor in two different laptops (a Dell and a MacBook) when using as regular computer. I tried to use the standard advise of depleting from time to time the battery and charging completely etc to no avail; after 3 - 6 months the battery life will go to down to about an hour and after one or to years it will last only a few minutes.

My new battery policy? I don’t use it. I just took it out. Some place recommended leaving it at 40% capacity and storing it in a cool place, so that’s what I do in my house and I just take the battery along when traveling just in case.