The quick answer is – Yes and No
I know this can be confusing because some company’s say Yes, you can reuse Our Planks. If you are using the Planks properly then the answer is No you cannot reuse any Plank.
This not just for my Planks but all planks. A good Plank like my Planks are 3/8” thick. I have seen “planks that are a lot thinner and will not hold up under fire”, sort of speech.
My guess is you are buying Planks for the Cedar flavoring. The best way to achieve this is to set the Plank over the fire, after you have soaked it in water for at least on hour, and let it smoke. When you do this the bottom will char, this is good, it will release the flavor of the cedar and add that great cedar flavor you wanted into your food.
Another way is to cook using the "indirect method" your grilling Planks will have the best chance of being reusable. As I always say half the smoke half the flavor. For charcoal grills simply set the coals on one side of the grill and the grilling plank on the other side. Likewise, for gas grills light one side and place the plank on the other side.
Technically, if the grilling Plank is still in good shape after the initial use it may be reused. Keep in mind that it will take on the flavor of whatever you grilled on it, and some of the essential oils from the wood will be used up from the first round of grilling.
Here is my top secret way to reuse the Planks. If you are using charcoal place the used Plank in small pieces on the coals. Not all of if just a few pieces. They will catch on fire and release that Cedar flavor just like you were using them to hold the food on top. I cook on a Plank one time then reuse it on the fire two or three times. If you are using gas place the cedar pieces in a metal pan and place them on or near the fire.
I hope this helps now let’s get out there and grill something