I transitioned for 2 years and didnt suffer any breakage...I did a ton of protective styling with sew-ins and I didnt use protein treatments more often than every 4-8 weeks. I used light protein treatments - homemade - avocado mixed with coconut cream, yogurt, an egg yolk, banana and honey. Though they were light I followed them with a moisturizing deep treatment. I alternated between the homemade pro treat and black tea rinses. I even tried an amla rinse as well.
When moisturizing and sealing I used the moisture based products heavily on my natural hair and focused less on my relaxed hair bcuz my natural hair loved heavy products and my relaxed hair didnt. I never baggyd my ends bcuz that made em mushy and limp. I agree with Aireen, and speaking from experience I wouldnt do protein treatments every week, that is way too excessive but I would DC every week, moisturize and seal nightly and protective style. Another thing that helped me was sealing my ends with shescentit seyani hair butter. It is a light protein but it strengthened my ends instantly after application.
I also agree with bun mistress, I only detangled my hair under running water in the shower with my hair saturated in conditioner and after doing an oil rinse. I also did everything in 6 sections as well. If I wanted to style I waited until my hair was mostly dry to manipulate bcuz it was extra fragile with those competing textures.
Hope this helps u!