We recommend waiting until your baby has good head control and can open his legs in a squat (at about 4 months).
Back carries give you a new mobility and take you to a new level of babywearing.
You can try several back carries, depending on your needs and on how confident you feel.
Back PWCC (Advanced Pre-tied PWCC on the back, with the help of another person to put baby on back) is a nice and easy transition to back carries.
Double Hammock (and its variations) is very confortable for both the wrapper and the wrappee, but it may need a bit of practice.
You may feel more confortable with back carries after coming to a workshop where an experienced instructor can give you useful tips.