I've got an 8 week old and am still using muslin squares - he was 10lbs so was a big baby , and has explosive poos - I've found the muslins really successful, the poos are no less contained than using a disposable, and the muslins wash up (I rinse poo ones in a bucket first) without leaving a stain - plus they dry in about half an hour! I used fitted nappies with my first baby - and they were massive and bulky on her at first - so am really happy with the muslins as they let my little boy stretch around so much more. 24 muslins cost me ?15 - so its really good value for the short time they can be used.