Travel Technology - Laptop power: battery or converter?

Okay, a couple of novice questions:

During the next few weeks, I'll be using my laptop most of the day. I can run it either on the battery or use the charger/converter.

Is it better to run it off the battery and then recharge when the battery is down to about 10% or so?

Or is it better just to keep it plugged in?

Laptop performance shouldn't be an issue (I won't be using CDs, etc.), but I'm wondering which way is better for the battery.

The nickel cadmium (NiCad) batteries they used in laptops ten years ago had to be discharged way down or they'd develop a "memory" of how far they can discharge and not go below that. That cut how long a computer would run on its battery.

With today's lithium-ion (LiON) batteries, or even the slightly outdated nickel metal hydride (NiMH) kind, it shouldn't matter.

(Corrections welcome.)

Personally, I keep mine plugged in because I never know when I might have to run it on battery for a while and like to keep a full charge.

As I understand it, these batteries have a finite number of charge-discharge cycles. So every time you use it down to where it needs to be plugged in to an AC source, you're using up one of these cycles. Not so if the computer is continuously plugged in and the battery is neither charging nor discharging. Anyway, that's my understanding.

Thanks. I've been keeping it plugged in, but I wasn't sure that was the best thing to do. At the price of a battery, I certainly don't want to shorten its life.