When plastics are cooked correctly, they'll last forever. The colorants may change over long periods of time, but the plastic won't change...as long as it's cooked correctly, initially.
I had a bunch of baits and scraps that were recently thrown out. The bags were tossed into totes that were headed for the dump, themselves...uncovered. I got called back to work 2 days early so the totes (containing the baits/scraps) sat outside for the few weeks I was gone. The sun bleached the colorants...You couldn't tell what color they were.
I had quite a few packs of store-bought baits in some tackle boxes, that I've had for 15+ years...they were as good as they were when I bought them (they've been remelted)...mostly H&H. So, Soft Plastics have a Shelf Life that's longer than Your own, but You should definitely protect them...mostly from exposure to sun. If moisture gets to them, they'll turn cloudy, but that moisture-cloudiness will go away if You set them out to dry. The moisture-cloudiness goes away overnight once You set them out to dry.