Keep them damp feed them once a week with a small ball of soft mashed spud (i use Asda powdered about 40p a packet ) and keep in a cool garage off the concrete floor and will last months.

The main thing is to keep them at a consistant temperature, as it’s vast/quick changes that do them the worst harm. I keep mine in a cool bag on the bank in warm weather, and then in my bait fridge at home. Just make sure they’re away from maggots in the fridge, the ammonia does them no good either!

No reason why you cant keep them a few weeks, had match packs (in the plastic tubs) for 6 months plus by feeding the worms! (cold mash potato, no milk and butter, definatly no salt!)