oh i am going against the trend here LOL! N is quite a hot baby and DH especially is PARANOID about him overheating... so i basically only use 1 tog bags... and use a long sleeve, long legs body suit underneath... that said we keep his room at 22 degs all night so that works and we use the same bag tog all year (so far!). I do have one 0.5 tog and one 2.5 tog for when we go away or for extreme days/nights but thats how we do it...
will see how that goes in the depths of winter though!