The battery life is important as that truly affects all other aspects of a tablet's functionality.

From design to features; performance to comfort, it's always best to inject your brain with all aspects of a product, swirl them around a bit and wait to see which ones rise to the top for you, reports CNET.com.

Tablets are tested usually to check and compare the longest battery life, along with other aspects such as performance, stability and comfort.

The usual test is to put the tablet on airplane mode and adjusts the brightness to 150 candelas per square meter. Then a 720p version of "Toy Story 3" is played to track how long the battery survives.

Amazon Fire HDX 8.9

The 2014 model of the Fire HDX 8.9 with a solid list of improvements, simultaneously maintains the characteristics that initially made the Amazon tablet a success. It features the cutting-edge Firefly item-recognition software, faster performance and an impressive set of speakers. Though battery life isn't a significant improvement, it'll last about 10 hours of watching (downloaded) Amazon Instant Video titles.

Apple iPad Air 2

Apple’s improved iPad Air with a faster processor and thinner do not have ‘improved’ battery. The iPad Air 2's battery life is about 10 hours of use on a full charge.

LG G Pad

The 7- and 10-inch tablets are simple in design and features, and are affordable. The larger model has a longer battery life than the smaller one but the small one's screen wears their matching resolution better.

Lenovo Yoga Tablet 2

The Yoga line features a useful built-in kickstand, and one of the latest models has a projector. The eight, 10, and 13 inch models all have 13 hours of battery life which almost three times some cheap tablets and with such a utilitarian design, they make great companions in just about any situation.