I make a lot of clothes for my grand daughter. This is cost effective for me and it also enables me to boycott the sweatshop countries. When she was a crawler I made a pair of pull on denims with a deep hem. When she started walking and getting taller I let out the hem and put red rickrack around the faded spot where the hem had been and some eyelet trim at the very bottom. She was still able to wear them after she got out of diapers and into panties. She will be 5 on the 23rd and she still wears those things as play out britches. They are mid calf crops and she knows GranMarty made them when she was a teeny baby. If you have shorts for a diaper baby don't toss them. The absence of a diaper will leave enough room for at least 1 more season of wear.
Pants or jeans with trim at the hemline look really cute as they start to creep up the calf. Most kids grow taller long before they get larger in the waist so pants can be worn for a long time as long pants, pedal pushers and then cut offs or hemmed shorts.