For me, the key to success with the Rootie by Voluum instrument is: (The 1.5 inch was perfect for my mid-length hair, past the shoulders).
1. 320 degrees is plenty hot enough. Any hotter, and you can damage your hair.
2. I only use this tool 1-2 times a week. Any more and I think it would lead to damage.
2. Do not "clamp" down hard and long. The goal here is not to "crimp" your hair. That's not the purpose of this tool.
3. Only use it on the roots and on the "under" sections of your hair - never anywhere else.
4. NEVER hold the hair between the clamping tool for longer than 2-3 seconds. Clamp it, open and remove the tool, and check the volume. If you think it's not enough, do it again for 2-3 seconds. But trust me, there will be more volume there than you think when you do this in several sections and then proceed to style - avoid using it on the thinnest, baby hairs near the face. I find those hairs are not strong enough to sustain the heat and they're harder to hide the clamp marks if you hold down too long/too hard.
5. No matter how 'thin' you think your hair is, you always want to use this only on the roots UNDER the top layer of your hair, never on the outer layer. So, using a comb, fold a top section over, clamp the under section at the root, and release. Do the other side and the back, near the crown.
That's it - for me, the whole thing takes less than 5 minutes, but it does create lift and volume. My hair is about two or three inches past my shoulders.
Lastly, I use the following after-shower hair products: Aveda, Pure Abundance Style Prep, Aveda thickening tonic, and BB Don't Blow It Thick Hair Styler, (yes, I DO realize it's for people with thick hair. Buy it anyway. It's a miracle worker). I use all three of these on towel-dried hair, then dry it with my Dyson dryer. All of these things combined have been a game-changer for me (oh, and following the "Fine Hair Friends" group on Facebook - lots of great tips there).
I do believe this product was worth the money for me.