My youngest is almost 21 months and still loves to be worn pretty much every day (see my siggy pic) - usually on front! he likes to cuddle
I don't wear him for long periods of time though unless he falls asleep or I'm trying to get stuff done and he's content. With four little ones sometimes it's easier to have him strapped onto me and I know he's not getting into trouble.
He often brings me a carrier (he's partial to a wrap or mei-tai but we use SSC exclusively while out an about) he say's mama, me! up up! So funny, how could I say no to that. And as long as I get the carrier tight enough and positioned right it is comfy. He's about 25 lbs.
Also, grocery shopping and other errands he usually is on my back so my hands are free to grab stuff. My 3.5 yr old rides in the front of the cart and the two older ones walk so it's the easiest way to go to the store.