I am having this problem now, actually.
I can tell I have been using conditioner too often when my hair starts getting limp and hangs there like an awkward curtain. My curls loosen, and my hair sometimes looks a little dirty. I usually just do a low-poo and let my hair rest with the conditioner for a day or two.
2b/cFi, low density, normal porosity, high elasticity
Low-poo: Trader Joe's Tea Tree Tingle
Conditioner: Suave Naturals (whatever scent I have on hand)
Styling: Paul Mitchell Round Trip, Tresemme Climate Control Finishing Spray
I'm a hair minimalist: the less time I spend on my hair, the better.