I'm thinking about getting blackout curtain linings for my dd's room - she's 7 months and currently sleeps until 7.00 am which is great, but I want to make sure she doesn't start waking earlier when the mornings get lighter. I've heard good things about blackout linings - I do worry though that if she gets used to them she will then have trouble sleeping when we go away if the room is lighter. Anyone got any experience of this? Also, where's the cheapest place to get them? Thanks!