My players use their down time to train new skills, aquire new gear and live life. Usually this is covered in a fluff format... ("ok guys you have had 3 weeks off before you could land an other run. What did you do in the mean time?")
Other times, I use their "off" time to throw a plot or adventure hook at them... While these aren't runs in the traditional sense, they do make the world come more alive for the players. ("So John, you're sitting at the bar nursing your drink and trying to get comfortable with your healing ribs after that 4th floor swan dive last week on the NeoNet run. A waifish, plain faced women has been eyeing you and occasionally smirking to herself. She gets up an walks past you on her way to the door... 'had a nice fall?' she mutters as she passes you")
These can lead to interesting times for the players, or new contacts, or a world of hurt... But rarely do they get 'something' for free...