We sprung for the deluxe(99.00) model Snugli Cross Terrain backpack (more padding, along with other improved features). You can use it from the time the babies are sitting up until they are 3 (which seems the longest time to use any baby item!). My 6 month old loves it...never cries...enjoys everything from our perspective. I can walk two dogs with her...I can do a day of walmart and grocery shopping without my infant shedding a tear. The other day and she just feel asleep on my back...like in a little pappoose. It is so nice to go grocery shopping and to be able to leave your cart--baby always with you...and she interacts with all the people because they are at her level, so she never feels left out. My back is sore after having her on at first, but if you use it often you just get stronger. I feel she is safe and secure in it, and happy! I bought it after reading these reviews. HIGHLY RECCOMMEND!