Besides sheer daily vaping quantity (ml per day consumed), seems to me that another factor making it easier to get into the 150ml Club is the number of juices vaped daily. If someone tends to vape the same one or two juices all day every day---and for weeks or months on end---chances are better of making the club. How one vapes matters also: high-voltage vaping or multi-coil cartos burn through juice much faster.
I'm a "bumblebee" vaper. I flit from one flower (juice) to another, sampling the nectar, then quickly moving on. Taken out of poetic metaphor, this means that I vape 15-20 different juices daily. I'll vape one juice for anywhere from 30 seconds up to five minutes, then switch to another (that's why I keep 20 PVs on my desk either carto or tank loaded). I may revisit a current favorite juice six or seven times throughout the day, of course, but I never vape any individual juice for more than about an hour total. All told, I might go through 5-6ml of eliquid in a day, but often no single juice gets more than about 1/2 ml. Every now and then, I'll go on a tear and vape 2-3ml of a single juice, but that's rare.
The only exception is when a carto-tank floods or leaks and I end up wasting a significant amount of juice through repeated (and failed) refills. But I assume that juice inadvertently swallowed (through flooding) or spilled on one's hands or desk (through leaking) doesn't count.
Although I've bought or made more than eight liters of juice in a year of vaping---that's 8,000ml---the closest I've come to consuming 150ml of any particular juice is Bounty Hunter by NLV. I've actually vaped about 60ml of BH, with another 90ml steeping in my stash. I've gone through 30ml of a whole bunch of juices, but not even close to 150mls of any one juice.