I cycle through 7 flavors from EC Blends. I have a monthly vaping budget that allows me to order 5 50 ml bottles per month (plus samples of other flavors if I can't resist). I stagger the orders to keep a full 7 flavors available at all times. If a new sample flavor is good, I ask myself which of the 7 to replace. Usually, the new flavor ends up on my "holiday list".
As to actual usage, I have a full set of 7 Resurrectors loaded, each with a different drip tip so I know which is which. They are for casual vaping. The daily workhorse is a 3.5 ml clear tank with a Resurrector carto inside. I fill it with one of the seven, matching drip tip to flavor just like the individual cartos.
It took a year for me to get this system up and running, but it really works for me! I don't run out of flavors I love (let alone liquid), I know at a glance if I need to order more hardware, and I stay on budget so I can save some money for the next shiny toy!