I have really incredibly dry, thick hair. The discovery of heat styling right before high school fried my hair for two years straight. I chopped several inches of damage off junior year and went CG but I'm still struggling with my natural dryness--I've never had split ends, but countless trims and cuts have never eliminated my awful, kinky, frizzy ends.
I've noticed that amodimethicone (this product contains it) really helps my hair wrt shine and softness. That's what motivated me to pick this up in the first place. I've never experienced build up from this even though I co-wash, so don't let that stop you.
When I first got this, it was my only leave in product besides my conditioner. I would put some GVP conditioning balm in my hair after my shower and then unscrew the top of this and pour it into my hand--a little spray doesn't cut it with my hair. The texture of this is very light and slippery. I'd apply this straight to my hair and when it dried, it would be a bit less frizzy, with amazing shine and so soft, and virtually tangle-free except for my perpetually pesky ends. The downside was that my hair would still be fairly frizzy and I was going through the bottle really fast.
Now I use Garnier Sleek & Shine Leave-In Creme as my primary leave-in conditioner. This is just the cherry on top. I apply my GVP balm, a bit of coconut oil, Sleek & Shine, and then about 4 sprays of this. The shine is still there and I never need to untangle my hair anymore.
For someone with less dry hair than I have, this will be a great leave in on its own. If you recognize your situation in my hair, though--I suggest the method I've now developed. This really smells too good and makes my hair too shiny for me not to repurchase it :)