I would do some searches on "roof sealing" or "roof seal" and see what you find. It is covered frequently on the Forums.
Each roof has it's own characteristics like being in fairly good shape or bubbling, having loose sealants, color problems, weather checking, etc. so it's difficult to suggest "do this". Some pictures or a description, at least, of your roof would certainly help. In most cases, a name brand EPDM rubber roof should last many years. If a leak does occur, it is typically around an opening or at the edges of the material and not through the rubber membrane.
Your Starcraft is getting towards the age where some repair and sealing is in order, if it's never been done. The edges around vents and pipes, the joint where the roof ends and the front/back walls meet, and the roof to sidewall joint are good places to start resealing. IMO, there are two products that standout for RV roof repair---Eternabond Tape and Geocel Tripolymer sealant. There are more than a few threads on the Forum about those and I think you'll find many pleased users. Another sealant that is commonly used is Dicor, both self leveling for horizontal surfaces, and non-leveling for vertical joints. I haven't used either but they are frequently used by the Mfg.'s of TT's and users on this Forum.