Some recipes work almost straight away.
Some are only good fresh and get worse after they steep.
Some aren't good until they steep.
Nothing to do with DIY vs commercial, it's a function of the recipe.
Agreed. I have a PB&J recipe (posted in another thread) which is simply delicious when freshly mixed. However, after a month the flavour is very muted. Still vapable, but not nearly as enjoyable as when mixed fresh.