Yeah I also think it has a lot to do with technique, appliances, heat levels, and products you use. I have found that in the past when I would heat style, I used to think that I needed the highest level on the flat iron to straighten my hair... Even with heat protectant, I had BREAKAGE, and then to top it off, I was heat styling almost every day or every other day.
I've now learned to only flat iron on the days that I wash and deep condition (which is during every wash), I apply leave-in, moisturize and seal, then put a bit of serum when my hair is wet and allow it to airdry. Then I go off and flat iron. My flat iron is only on a low temp - never more than the 284 degree setting. I have an awesome flat iron that is both ceramic and tourmaline. Now my hair comes out shiny and healthy, and I dont use any more heat until my next wash. The days in between I either pin curl, or up do it. That saves my hair I feel because it balances out when I use heat and when I dont.
Most importantly for me though, I read in Cathy Howze's book to not use "double heat." So for me, I like to airdry then flat iron. I try not to blow dry and then flat iron because that's too much heat. If I do use my hooded dryer I leave it on cool or low heat. I will from time to time do a quick concentrated blow dry (with a hand held dryer) on my roots to get em straight only when needed.