This is a great link for helping to determine whether or not you need protein.
But basically, to sum it up...your hair texture/porosity and its elasticity play major roles in determining whether or not you need protein. If you have hair that is closer to the coarser end of the texture spectrum, then it is less likely that you will need protein as coarse hair already contains a lot of protein in its structure. Since you have medium texture, your hair texture won't help you determine whether or not you need protein as much. If you have porous hair, protein will help "plug" the holes in the hair cuticle to prevent moisture from exiting so readily. The other major factor is how easily your hair breaks. Next time you're in the shower, see how much your hair stretches. If you pull out a few hairs and stretch them, do they seem to stretch a lot before breaking or just snap? In general, when your hair is dry or wet, does your hair tend to snap easily? If so, it's likely that you need moisture. If your hair feels hard, you probably have a build up of protein. If your hair feels mushy, you likely have a build up of moisture. Make sense?
Type 2b/2c, med/coarse, low porosity, medium density
Co-wash: Suave Naturals Tangerine, Live Clean Moisturizing, CJ Daily Fix, GTTT, Tigi MM
Conditioner: Tigi MM, Jessicurl WDT, CJ Curl Rehab, CJ Daily Smoothing, CJ H&B Deep Fix
Deep Treatment: same as rinse out
Leave-in: KCKT or my rinseout
Styling Aids: Alberto/V05 Gel, HETT/HESMU, KCCC