Mine vary from 5 to 8 ft. I never deploy my noodles in open water. Always in coves and mouth of creeks. I like to set mine so they will drift across to a wind blown bank. This way they cover a lot of territory. Also makes them easier to find. I always try to keep them in sight while I fish other ways with rod and reel. When they stand up it will tell you there is a fish on or one has bit. Once a fish is on they will usually make their way to shallow water where they can lay on the bottom and not have to drag the noodle. They tire out really quick. I take mine up when I leave the lake regardless of how long I fish that day.
Great advice here^
You can leave them over night, but you really need to anchor them if you do. But you give up covering lots of water going this route, tho. Otherwise you will likely lose the jugs or the fish will drag your setup around for days or until it dies. Or, someone will collect your jugs for you. I add 1/4 to 1/2 ounce of weight to keep the bait at the target depth. If you don't, a good wind will push your jug along faster than the bait, causing it to rise up in the water column.
Oh and bring binos if you're going to let the wind push them a ways. It can be tricky to spot them at a distance in timber and/or if there's a little chop on the surface.