When using Laptop at home, I use AC Adapter without taken out Battery. Is this correct way ? Or I have to take out Battery ?

My friend say: if I don't take out Battery when using AC Adapter, the battery will finished quickly. That means I have to buy a new Battery ! Is this true ?

Normally, a battery can use for how many years ? How to make it last longer ?

Usually is a good idea to use the battery on its own until the battery is low then you can plug in your AC adapter, but I don't think is a good idea to take out your battery when using your AC adapter because it might cause unforeseen problems.

I would recommend you to use the battery on its own and only plug in the AC when the battery is low... But that is only my opinion!

If you remove battery and run on AC only, then if there is glitch or outage, you may lose work.

I use a laptop and I never really thought about it, but I always use it on ac adaptor, and my battery died very quickly, to the extent it won't hold the charge now for more than ten minutes if I eave it unplugged and try to use it! I don't know if this is why, but it may be!

This used to be an issue years ago when nickel-cadmium (NiCad) batteries were used. This is not really an issue with today's batteries (Lithium Ion) and it will make no difference in the life of the battery whether its in or out. Stratmando is correct, you will lose work if the power goes out... or as what happens around my house, someone trips over the power cord and unplugs it. Additionally, if it's not in the computer, the battery will lose a charge over time so when you do need it you run the risk of not having it fully charged.

You can expect about 2 years of life on most newer batteries. Possibly longer.