While gliders don’t require as much space as a porch swing, they still need adequate room to rock back and forth. I recommend giving yourself more space than you think you’ll need. However, you’ll need two feet of clearance both in front of and behind the glider, at a bare minimum. Keep in mind that this doesn’t account for other patio furniture, traffic on your porch, or where you’re positioning your glider. A glider is, however, a good alternative to a porch swing overall if you want some of the same use without sacrificing quite as much space.