This is because Yavin Station is a constantly changing location. For some X-Box users, the initial excitement of Yavin Station might have worn off quickly because it isn't immediately apparent what treasures it might hold. While the PC version of Knights of the Old Republic comes with Yavin Station, the X-Box version requires a download through X-Box Live (It can probably be acquired though the demo discs of certain overpriced and poorly-written magazines, but I'll leave that up to you). Just try to earn all the money you can in the meantime, because Suvam's premium goods are extremely expensive.
They must be appropriately spaced apart (as explained below), and you can't skip any visits.
Note that you will not be able to access all the items if you don't make all three visits. There are 26 exclusive items that can only be acquired by making three well-timed visits to Yavin Station. New Planet: Yavin Station Downloadable Content on X-Box Live.
