For the most part I find that only devices that have forced air cooling, aka fans, have issues with dust. And in those cases it is defiantly a good idea to clean them out regularly as overheating is defiantly an issue with enough dust accumulation. You would be amazed the amount of dust that will accumulate in a PC, even after a few years. In the case of computer cases you can get filters that help a lot however you need to make sure you clean the filters out or you will just be making the situation worse.