I leave to go to my boyfriends house almost every other weekend. Before I leave late on friday night I do a good clean of the cages and make sure that water (I usually add another waterbottle just in case one stops working too) and food dishes are full or heaping. I also thoroughly spoil them with a lot of cheerios and have an extensive out time that night. When I put them back into their clean cage I do a full check over for lumps or squeeky breathing or anything else unusual and then put them into their cage. Before I walk out the door I say bye what seems like 10 times (as well as check that the cages are closed and secure far more then 10 times). Then I leave.
Of course any rats on meds come with me or anyone who needs to be watched will be carted along.
Then the first thing that I do when I get home is run in to see them. I'm only gone 2 nights and 1.5 days and I am forgiven when I spoil them with a yogurt drop or a puffed yogurt coated treat when I get home (that is the only time that they get stuff like that).