It does say 6 months although I know a lot of people swap it over a lot sooner.
Lily is 17 and a half weeks and still in the carrycot. I have tried to make it a bit more interesting for her by putting a cot book in there and a whoozit activity spriral on the handlebar.
If you are using the car seat on the frame, the guidelines are for no longer than 2 hours which is why we don't use it. Better to use the buggy in the fully reclined position than the car seat IMO.
Proud Mummy to Lily May, born 21st July 2008 at 38+4 and weighing 7lb 11.5oz.