I'm natural but I wear my hair straight pretty much all the time. My natural stylist always charges me at least $65.00 to straighten cause she says it's still 'virgin hair' (i guess she means, not heat trained yet) cause when I wash it, it reverts right back. Paying that kind of money every 2 weeks got costly. She also wanted to trim my hair every two weeks as well, and the last couple times, she refused to use a heat protectant/oil/serum or anything to straighten with!! So After a couple months, I just started to do my hair myself. Now I can wash and straighten every week...and all it costs me is my fhi iron and my chi blowdryer...one time payment
I went to her for twists, but my hair was not as long as I liked it, so I haven't gotten twists yet, maybe in another year or so, when it's longer.
I voted every 3 months. More like every 3-6 months, I basically just go when I want a trim.