In general, it's best to make sandwiches as close to eating them as possible to avoid the bread getting soggy. But I do have a few tricks to help avoid soggy sandwiches when you have to make them in advance! If you follow these tips, your sandwiches should keep well for up to four days in the fridge. The first trick is to spread a thin layer of unsalted room temperature butter on the inside of each piece of bread before making the sandwiches. Butter acts like a barrier and repels moisture from the bread. As a bonus, it adds a bit of rich flavor! (And if butter isn't your thing, you could use a thin layer of mayo or cream cheese instead.) Additionally, make sure that you're not using a watery chicken salad. If your salad looks like it's on the watery side, I recommend straining it in a fine mesh sieve set over a bowl to catch the liquid for about 20 minutes. Also, don't add watery ingredients (such as tomatoes). Lastly, the final tip is to store the sandwiches in an airtight container layered between pieces of parchment paper.