How much battery life will I realistically need?

I'm thinking about getting a new laptop for college since my old laptop only has a measly 1.5hr of battery life, in addition to having below-average specs in other areas.

I'm going to be a computer sciences major and plan to take my laptop wherever I go. Usually, I'll either be browsing the web or working on programming projects while in places such as restaurants, libraries, or rooms. Once ever two weeks or so, I'll be working on my laptop for up to six hours nonstop.

I'm getting tired of dragging my power cords across rooms, so I'm looking for something with a good battery life. However, I am not sure that I'll realistically need something with a 6-8hr battery life because docking ports can be found once in a while.

What should be the lower bound for battery life?

I already know what laptop I want. Generally, I work with the backlight set to one of the dimmer settings, and I'd be on the internet all the time. Yes, I am actively working for all the time. Otherwise, I turn off my laptop, even for a bathroom break.

That 2-hour battery life while you are actively working is not bad. The wireless burns a lot of power, as does the backlight on the display. The rest of the laptop doesn't use much when you're not actively working (unless it's a REALLY old laptop), it goes into a low-power state.

I'd set the upper limit on how long I was going to actively work at 2 hours. Anything longer, and I would want to use a docking station in my room with a real keyboard, mouse, and monitor. So I would just continue to use my laptop as is, or get one with just a 2 hour battery life. If it became a problem in practice, I would buy an extra battery later, and keep a charged spare in my backpack.

You haven't mentioned the laptop itself or your disk drive requirements. Drives eat battery life.

If you aren't using the disks, turn off Wi-Fi, Bluetooth etc and all power hungry items you would extend you battery life quiite a bit. Turn them on and........

Smaller screens use less power, weigh less.

You might consider buying a second battery and a charger. That way you can always swich batteries if you get low. I have never seen a battery go 6 hours on a laptop under realtime use even with everything shut off.

For my laptops, I've always gotten the best, longest-lasting battery I could get. I think it is a worthwhile upgrade for any laptop because as your laptop ages, the battery-life will go down. If you start with the best battery pack available, the decline in battery life will not be as noticeable or inconvenient.

The best thing you can do for battery life is use Windows XP, vista destroys battery life