Unless I'm doing a blown out fro, blowdrying alone does nothing for me. If I'm trying to straighten my hair, I HAVE to flatiron it. Since I'd rather not put both types of direct heat on my head, I airdry or rollerset prior to flatironing.
I'm trying a method right now where I blowdry on cool/warm once a week after I dc using a comb attachment. I really hate airdrying I end up with ssk's. So far so good. I will only flat iron once a month. I ve been doing this for the past couple of weeks and I haven't seen an increase in breakage yet. For the past yr I got into a bad habit of doing both and I didn't retain any real length.