Moderator's note:
Posts from new members in the early hours often get followed by 'helpful' links from ther new members. If such a link appears here I'll simply ban both posters, resulting in the swift disappearance of this thread.
However, assuming for the moment that this is a genuine post, battery life can vary widely across different devices and depending upon how they're used and charged. See here:
https://www.androidauthority.com/maximize-battery-life-882395/
Most batteries last at least two years though and some can last for far longer than that. Many phones have batteries that can be replaced as easily as changing torch batteries but some have batteries that can only be changed by a specialist technician. Somewhat annoyingly, it's often the most expensive phones that have to be returned to their manufacturers when new batteries are required. However, for those who're prepared to take the risk, there are often videos on Youtube showing how new batteries can be installed directly by phone owners.
The same general principles apply to batteries in tablets but it's then more likely that the assistance of a specialist (or referral to a Youtube video) will be needed to replace a defective battery.