With #3 on the way in 9 weeks or less (when did THAT happen?!?!), and a new home purchase on the horizon, I'm thinking about potential ways to gate off our living space. I think there are various way that gates can keep kids of all ages safe from household hazards, safe from each other, and can help keep me sane in terms of containing mess.
Currently I only have one baby gate - it's in the doorway from my kitchen to the stairs, which go down to the bedrooms/main entrance to the home (we live in a 2-family brownstone, so layout is a little atypical). Originally it was there to prevent my younger DD from going down the steep stairs by herself and falling, but now I use it to keep both girls (2 and 4 years) from hauling their stuff up and down stairs from their bedroom to the living room without permission, and from coming back into the kitchen/living room when they're having trouble staying in bed at bedtime. I may add another gate between the kitchen/family room when the baby arrives so that I can safely use the bathroom/turn my back and the older girls cannot access their sister. In some of the new homes we are considering, I might gate off the living room as a play area, in hopes of containing the toys to one room.
Where in your house do you have baby gates, and what purpose are they intended to serve?