I have a Toshiba laptop that has the uptime of an average server. It was part of their Qosmio line, the gaming laptops of their day, and weighed about ten pounds making it difficult to lug, so the thing has pretty much been on and plugged in nonstop since 2010 or so. It reboots maybe once every two months to complete Windows 7 updates.

Never had a problem with it. Not sure if batteries are just getting worse or if it's a result of the trend of trying to make things thinner-and-lighter such that there's not room for the battery to expand as it's likely to do over time without exploding.