I would think its pretty usable right out of the bottle in most cases, its the stuff you have made from custom companies that makes hundreds of flavors and formulations of each
Johnson is a company that makes huge batches and its probably ready to go once you get it (more or less) since its already been sitting for a undertermined length of time, but with anything else this may or may not always be the case and if it dont taste right let it steep cause it could be a newer batch
Now like Mt Baker Vapor its fresh made as you order and steeping makes radical changes, transforming changes, since it was made basically a few days before you have it in hand