The battery is non-existent and now the hinge has started to fail pretty abruptly! It's pulled the right hand side corner of the controls away from the main board

It is four years old and experiences pretty heavy use, so I am not grumbling! I never use the LT for gaming, video editing or anything particularly high end. I browse the net (too much) and stream videos; that's about it. I quite like the idea of getting more familiar with software like Photoshop but I have said that before!
Budget? Value for money, bargain, free........something along those lines.
Advice Gentlemen please. I especially want feedback on battery life and whether you use laptops or desktops. My battery on LT's always seem fine at first and then rapidly go down hill. Is there a protocol for long life that I am not aware of? (Batteries not me)