I don't have one but I think I need one when I go check the letterbox/do gardening/hang washing out/drink my coffee outside. House too small really to justify right now but might consider it when we move (as soon as we find a house).

Went to a party last weekend and borrowed my friend's while there because my baby borrowed her son's cot. Was fantastic because I could happily wander outside and know I could hear her if she cried.