My hair LOVES protein, so regular weekly usages works well for me. I have colored (dyed) hair and have been able to maintain length without breakage. Right now I'm working on density issues so protein is part of my plan but I've added henna/cassia glosses to the mix.
But, early on with my Megatek usage, I've been able to reverse my high porosity down to normal-high. I used to have issues with my hair drying so fast that I could stand under a window fan and dry in 5-10 minutes with or without product. Now I have normal drying times. Long term, I think you hair gets used to it, so in recent months I have been rotating products more frequently. But I haven't had any long term issues with weekly usage so I'm pleased with it.