The more you send out, the better your weekly review will be, basically. If you're making a comfortable amount of money, though, it's just extra. You don't have to send EVERYTHING out. Especially low rank stuff. You will not get paid for anything level 0 or special, I believe. Try to avoid sending anything under 0.5 MB's, as they're usually not good enough for good money, or usually end up special in some way. Anything else, you can send for extra money if you want to.