Do what tastes right to you. I steep (or age) liquids only as much as I can't vape all my liquid at once, so until I get to it - it's steeping. I don't use any special methods anymore either.
I usually try any pre-mixed
e-liquids straight out of the mailbox though, and if I notice a perfumy flavor or something that doesn't taste good, I might leave it opened up for a few days, giving it a shake every now and then. My DIY stuff, I usually let it sit for a few days and then start
vaping it.
I used to obsess over steeping, burping bottles, sitting for hours shaking them, putting them in a ziploc and giving them baths and such, trying them again and again, seeing if the flavor had changed.
Now, not so much. I've had so few e-liquids that I tried and didn't like turn into something I did after steeping, that it's not really worth the worry.
Now I will say that letting a bottle sit for a few weeks will often bring out other flavors in the liquid and will sometimes change how it tastes a little.
So there you go, force-steep or don't. But by letting liquid sit, you are letting it steep to a certain point anyway.