We took DSs 4 & 7, rented a double, & were grateful to have it. They didn't always both ride, but it gave us a place for the stuff & most importantly a place to give the kids a break from the sun. The boys are very fair skinned & it really makes a difference when we try to keep them out of the sun. My 7 yr old still wants the stroller.
I just keep reminding him that he'll be pushing me some day, so enjoy it while it lasts.