Who would have thought you can or need to steep the liquid...Now I have to do some more research..
You don't always, it depends on when the juice was made so to speak. If I grab a bottle at my local B&M I know its stood around in warehouse somewhere at least a few weeks and did its steep time. If its a vendor that dates their batches on the bottle then you know whether its had a bit of steeping time before it was shipped or if it was made the day it was ordered then it may need a bit of shelf time to mature.
And this depends, too, on the flavor. I know from DIY, you can vape some flavors right out of the mixer and have a great a vape as two weeks from the day it was mixed, while some need a time to 'mature', especially ( I have found) is you are mixing several flavors that need time to start working together. Its like a good wine - some need their time.
Some people never hear about steeping until they get a bottle of something that tastes like 'ick' and nothing like the same and complain - to be asked if they let it steep. It really can be amazing the change a week or two can give flavors.
Because the 'steep' time is so important to bring out full flavors I mostly order with the idea that they will be getting some steep and shake in shipping but still need some time on my shelf - that I can't order fresh juice when I am so low I need to vape it as soon as I open the vape mail. Think that is a plan most people use from what I have read.
I also use a few vendors that I know don't mix on order but make up their flavors as their stock gets low and so usually arrive with their "steep time' done.
Its fun to play around with some flavors and steep time if you have not had any steep experience, or known about it before. In the early days (and before I got in to DIY) I found reading about steeping a bit confusing and really wondered if it made a difference. So I ordered 2 flavors (one a fruit flavor) and let it sit on the shelf and a week and a half later (my fresh mix vendor is close and shipping is fast) I re-ordered the same order. So I had two bottle of the same juice, one each a few days old and one each two plus weeks old. I was shocked at the difference it made in the flavors.