Some spots are really tough to vacuum no matter what extension you use. If you put a toilet paper tube on the end, you can shape it to fit almost any nook or cranny.
A good vacuum cleaner will usually come with a few extra tools, but there's no way they can work for everything. Reddit user beeanchor13 found another great use for old toilet paper tubes. Throw it on the end of your vacuum cleaner's suction tube end and bend the cardboard to fit whatever you need to get into. This could be really helpful for vacuuming cars, offices or door tracks. There's a possibility that the tubes won't fit the end of every vacuum cleaner model out there, but a majority should be able to fit one way or another.