Are you planning to pick up HTC's Vive VR headset? Well, you may want to have a read of the Vive PRE development kit user guide to make sure that you have enough space.
The manual says that the minimum area of clear space that you'll need will be 1.5 x 2m (5 x 6.5 feet). This space will need to be free of clutter and furniture. Another consideration to bear in mind is that the 5m of cable attached to the headset will need to be able to reach from anywhere within this zone to your PC.
Mirrors, windows, and other sources of direct sunlight will need to be covered; HTC says that vampires are going to love VR.
Finally, there are two base station boxes that will need to be wall-mounted and can't be more than 5m apart.
It may be time to break out the measuring tape and double check that your home is Vive ready.