A lot of people here talk about Linux making laptops die really soon but I have no clue what the hell y'all are talking about. For me switching to Linux normally makes the battery go 2-5x slower. The laptop on which I'm typing (a T420) lasted half an hour on Windows 10 and two hours on Debian when it had the original battery, now that I've replaced it it gets 5hrs on Linux and maybe two max on Windows 10. About the same on Windows 7.
Of course it depends on how you configure it but if you've really de-bloated your system you can get much more out of the battery than Windows can. I've been able to get more battery out of a recent Inspiron, a less recent Toshiba Satellite, this Thinkpad, and an old Samsung netbook, so I could be biased by my hardware.
Nowadays it's much easier to get higher-level Linux support, too.
Of course it depends on how you configure it but if you've really de-bloated your system you can get much more out of the battery than Windows can. I've been able to get more battery out of a recent Inspiron, a less recent Toshiba Satellite, this Thinkpad, and an old Samsung netbook, so I could be biased by my hardware.
Nowadays it's much easier to get higher-level Linux support, too.