Choosing the right diaper is key to improving absorbency and preventing leaks. The weight indication on the package is a good place to start, but you should also consider your baby's age, what s/he eats and drinks, and how much s/he moves around. If your child's close to the end of the weight range on the chart, s/he might need the next size now. Even babies within the weight range can outgrow the absorbency before they outgrow the fit. And for leaks at night, try the next size up for overnight use only.