How fresh does a dog stool sample need to be?

(c/p)  Obtaining a Fecal (Stool) Sample from Your Pet:

Samples must be FRESH (still soft and moist) within the last 4-6 hours. Use a ziplock baggie turned inside out over your hand, or a disposable utensil, to collect a sample into a ziplock baggie. The sample should be approximately the size of a sugar cube, or 1/2 teaspoon.

Stool Sample Collection - Smiths Station Animal Hospital ...https://www.smithsstationah.com/ › stool-sample-collection

The fresher it is, the better the vet can do a fecal test.    You can ask them for a pot to pick up a sample, and then refrigerate it if necessary.

Doesn't matter dogs will eat fresh and dry t*rds. 

Fresh as possible, but it can be put in the fridge until taken to the Vet if needed.  If you don't know which of your dog's poop is fresh or not, the Vet can also take a sample when being examined.  They can do an anal swab.