We travel quite a bit with our little and always dress her in some sort of tracksuit so this is the perfect travel outfit in my opinion! Not too thick of material so we know she won’t get too hot or too cold. We bought size 4-5 for our 3.5 year old, she’s about a little over 3FT, weighs about 35lbs and this size fits her great! She’ll definitely be able to use this set for a good while!