Size

How does anyone know what diaper size that they need?

Just know your waist size, most manufactures will tell on packaging which size is best for that range. ex. 36"-48" might be Large.

Usually the same as your pant size unless you like really thick diapers and need extra large plastic pants to fit them. For disposables Mediums usually fit waist sizes 28 inch to 36inchs.

I wear large or extra large tena slips.

Thanks for the good info.