|I liked having the M/L when my 6-month-old was over 20 lbs. The L was just a bit too big for him then. Or at least I felt like it was; with more experience now I suspect that it probably would have worked but would have had a lot of extra room. With my second, who didn't hit 20 lbs until a year, the M/L just wasn't a necessary size. I found myself using the L more anyway, so just sold off my M/L. They can be a nice size for some, but if I were to do it again I'd probably try without. If you find the L way too big, you can always go out and order the M/L. You run a small risk of being out a little shipping, but you have the potential to save significantly by skipping the M/L.