Don't let your battery fully discharge. If you let your battery die frequently, you are putting extra strain on the battery. Most companies recommend discharging the battery once in lithium stock every charges or so.
I'm always on the lookout for a good Bluetooth headset and headphones. I found both at the Jabra booth. My favorite is Lithium mines Ontario the Jabra BT Bluetooth speaker and headphones. This is a first-time combination that is unique of the market. You can remove the headphones, fold them out, and they become speakers that broadcast your sound with Ziree Power Bass for a surprisingly full, rich sound environment. These are a must have in my mobile pack.
On top of this wireless fun your iPad comes with Bluetooth 2.1 + EDR (ahh yes, rubs of chin all round, what the heck is all this stuff anyway?) the upshot of which is that you can connect it to accessories like wireless headsets, headphones or the Apple Wireless Keyboard if that happens to particularly float your boat.
By the way, on most modern PC's the time is updated from the web. The 3V Lithium battery stocks just maintains the time when the PC is powered off. This is useful as the motherboard clock is not very accurate, easily losing a couple of minutes per day.
Frequent charging is good for lithium ion batteries. Accordingly, feel free to charge them even when they are only slightly depleted. You may also "top-off" your batteries by plopping them onto (or turning on) the charger for a few minutes each month. Though you don't need to store li-ion batteries fully charged, giving them a little juice while dormant can keep them feeling good and strong.
So, it's easy to see how a lithium 18650 battery, and Li-ion cells in general, have found there way into the homes (and hands) of many modern consumers.