Essentially, with Soundstripe, the more you put in, the more you'll get out. To put it plainly, the more high quality, useful (film friendly) tracks you have in the library, the more you get paid.
If we approve you as a contributor, you're a musical badass. So of course, we want you to be cranking out and uploading as much material as you can. We tend to encourage 4 tracks per month but there is no requirement.