Always check the Ubuntu documentation before you buy new hardware

Frequently I'm meeting Ubuntu users who bought new hardware and then realised that the installation of their devices is either very troublesome or in rare cases, not possible at all. To avoid such or similar unpleasant experiences, always check the Ubuntu documentation first. Hardware either a) works on the spot and is thus recommended, b) needs some extra installations/configurations or c) works only partially or not at all with Ubuntu. Optimally you buy recommended hardware components that work on the spot.
Usually you find guides at ubuntu.com. Examples:

Taxonomy: