According to this document (page 11) the shelf life for the cassettes is 1 year. The other ingredients (running buffer, DNA size markers, loading dye) appear to be standard reagents. Of those, the DNA size marker will probably have the shortest shelf life, but it stands to reason that the reagents should have a shelf life at least as long as the cassettes, seeing as only their shelf life is mentioned. It is possible to buy reagent replacement kits.