Actually, there are three considerations on how long (or short) cooked crab will last: > How the crab was cooked > The ingredients in the crab recipe > The temperature where the crab was placed
Steamed crabs or those turned into sandwich spreads or dips last longer than crab casseroles-- especially if the recipe calls for ingredients that are easily spoiled (like tomatoes or potatoes). Better stick with ingredients that can withstand hours or days unrefrigerated w/o being spoiled. Simple crab soups with less vegetables and more spices will last longer.
And of course, the temperature of the place where the crabs were placed. The cooler the temperature, the longer the crabs will last.
If you are going to travel and you're taking a freshly cooked crab dish with you, let the food cool first before you seal it in Tupperware or any other food container. It lets the vapor that comes from the hot food escape first which prevents prolonged exposure of the food to unnecessary water.