We had a 39L Engel, went to a 60L after buying a flash new camper trailer. After we sold the last camper and changed vehicles we also brought a Evakool Ice Box (didn't have dual batteries etc any more).
So at the moment we have a 60L Engel and an Evakool Ice Box, but I think I'd like to go back to a 40L, or perhaps 2 x 40L engels, one in the car and one in the trailer when we eventually get one. Well depends if I can convince Hubby, I think he's a fridge man rather than an eski man so the two 40L engels might be enough to sway him to give the 60L up!
We've got two kids who are growing fast, but a while till they're teenagers yet. Yet I must say we don't have any problem filling up the 60L even on short camping trips so perhaps downsizing isn't the best idea. Oh don't worry my Husband actually likes warm beer too (yuck!).