Over time, air begins to seep into the fluidline pot and dry out the product. This tends to happen with most cream products. You can extend your cream shadows by placing a piece of wax paper inside the lid to keep out the air.
One day, as I was sifting through my dingy 'Back to MAC' bag (all makeup junkies have them), I saw my old dipdown. It was half full; but, really thick and tacky. Cream products expire after a few months so don't try this with your Fluidline from 2 years ago (yuck)!
I decided to take my angle brush and see what it would do....Wowsers! Its aged like fine wine. My brows are amazing! Not overly done, but just right. I have more control over the fluid line. I can mimic my brow hairs without feeling like someone can see my strokes.
If you are a brow beginner or expert, give it a try. Let me know how you like it. Its only makeup. Nothing is permanent!