I just recently purchased a new laptop, and would like to know some steps to help my battery life span lasts longer. My last laptop battery life span wasn't long and it was only months before it wouldn't last longer than 15 min unplugged. I'm unsure if letting it stay on battery, or leaving it plugged in charging for many hours hurts or helps my total life span of my battery. I would like to hopefully have my battery life span lasts a long time so I don't have to purchase those nice inflated $200 replacement batteries from HP. Any tips are appreciated, thanks.

you can always go into the control panel and change the power management settings.

Depends on the computer. Most laptop websites have guides for specific models.
Nearly 15% of batterys for laptops are defective... If still under warranty, contact the builder
The batteries you get online through eBay and other sources have constantly been improving. We now find batteries for Lenovo, HP, Compaq, and Dell that last as long, or longer, than the OEM versions... at 1/3 the price.
The olden days of batteries that last three or four years are now gone... The governmental controls that are meant to control fire risk and such, have now resulted in placement of chips in the battery. The chips count the number of discharges and other factors. When the use of the battery reaches a secret limit, they quit... but generally they should last a year, and should last their promised hours right up until the year is over. It is a safety issue. I am certain money and profits have nothing to do with it. (heh, heh, heh)
We get very long life out of Lenovo Thinkpads... 4 to 7 hours... If you are not getting three hours on a full size laptop, and two hours on a cheaper laptop, you need to talk to the manufacturer.

Im pretty sure my old laptop had a defective battery but I have new hope in my current one which I paid alot of money for. In these hard times and in the future(1 year or 1 1/2 yr) it's still hard to find 200 dollers or $160 for a HP battery replacement. I was just always curious about the battery itself, and if what I was doing could negatively hurt the battery. I paid a good amount of money for my new one and im sure I got a good battery to power it as its pretty powerful laptop. One of my main concerns is leaving it plugged in, or unpluged most of the time. I figured if its alwasy charging the battery is always draining, killing lifespan. I generally just leave it plugged in all day, and once and awhile move it and would hope i get the hours the battery should last.

A laptop batteries should keep most of its capacity for up to thousand charge/discharge cycles. If you're not using the battery for a longer time, charge it to the maximum, put it in a water-proof plastic bag and put the bag in the freezer - this will significantly prolong its life.

Suppose to run the battery out then recharge it. Always have a backup battery ready. Charge to the max and put it away. I know one of the members here said to put in a zip lock bag and stick it in the freezer, but that's only if you're not using the battery at all.

Thanks for the advice. Im going on a 5 day vacation and leaving my laptop behind, should I take the battery out...maybe putting it in the freezer is a bit extreme.

Charge it then put it away (unplug) it. No you don't have to take out the battery out. No you don't have to put it in the freezer. Again the freezer would be ideal if you had a second battery and wasn't using it.

Tests show that freezing does little for any battery longevity or power saving or longer life while in use.

Keep batteries fresh was to place them in the refreg instead, but use a ziplock bag.