My kid is now a month and 4 days old and so far I have been on nappy changing duty. I am thinking of now investing on superbottoms (cloth diapers) at least for the night or to take him out. These cost a bomb. Is it worth investing in ? Also does anyone know the difference between the one that is for 620 and the one for 890? Also how long do these cloth diapers actually last (can be reused for) ?