I bought this when my daughter turned 8 months old. It was Fall and she needed to wear something underher tops to keep her warmer. It is Winter and she is now 12 months old and they still fit. I don't think she could wear them passed 12 months but it is of great quality. I washed them many many times and didn't tear or shrink. I bought 2 packs of 3 and would recommend it 100%.