Are laptops a bad investment?

Desktops are less expensive to get more powerful components, so it will thus stay useful longer for the same price compared to laptops. If you're more concerned with longevity than portability or style, go for a desktop. No matter what, you'll eventually have to buy a new computer after this one, but if you with a desktop you'll wait a while longer before upgrading or replacing. Plus, with a desktop you can just upgrade instead of replacing the entire system.