I started out at 18mg 4 years ago. Within weeks I dropped to 12, then 6. I stayed at 6 for a couple of years then dropped to 3. I tried 0 several times but to me, the taste is just off. I had 2 bottles of the same eliquid, one in 3mg and one in 0mg. The 3mg was tasty and delicious, but the 0mg tasted off. I decided I'd test a few other high name brand juices to see if it was all in my head. I loaded 2 different set ups with each and again noticed the 0mg lacked considerable flavor. The juice doesn't taste bad, just different from the original. For exapmle, I love The King by Kings crown. My local vape shop was out of 3mg in 30ml so I purchased smaller bottles in 6mg and 0mg to mix them down to 3mg. That tasted fine mixed. However I decided one night to try 0mg. It wasn't the delicious flavor I love, it was ok but nothing like the flavor I love.
I think a little nicotine adds something to the flavor. I'm satisfied with vaping 3mg and will stay there.