A laptop batteries is often pricey and has a limited lifespan. Proper maintenance will extend its useful life.

Periodically remove the battery from your laptop and clean the contact terminals on the battery and in the computer with a cotton swap moistened with rubbing alcohol.

If you have a fairly new laptop accessories, it most likely uses a lithium ion (Li-ion) battery. Li-ion batteries do not suffer from performance degradation from partial discharges (i.e., before the battery's power indicator goes to zero), so charge the battery every chance you get, even if you've only used a little of its power. Never let a Li-ion battery fully discharge.