Should I connect my sewer line when camping?

I usually don't hook it up until I need to, then leave it hooked up. But IMO, it's not a good idea to leave the gray water valve open. Why? Because even though you may be wiping dishes/pans out with paper towels before washing in the sink, there is still food waste that will sit on the bottom of your tank when the water runs out. Better to let it sit/float in water - besides, how big of a deal is it to open a dump valve when the tank is full? We use paper plates a lot but still use paper towels to wipe out pans before washing.

Secondly, when leaving camp, it is a good idea to dump the black tank first, then the gray which will rinse the hose of any particles that will be left behind.