I don't believe in cutting roots, other than those that are truly dead - ie very soft, greyish white and super pliable/droopy. I say this because I have seen the gnarliest and driest of roots sprout new growth, if care is ideal. Also I am now a firm believer of clear plastic pots with slits and "peanuts" as a bottom layer to protect against the plant standing in water. I think light entering the pot helps stimulate root growth.