If you have extremely curly hair (i.e. like a Type 4c), then Roller set service is the healthiest option at all times. Why? The curlier the hair is naturally means that there is more opportunity for the cuticle to open and makes it easier to break.
Even if you relax this extremely curly hair straight, you have permanently altered the strand which means it is weaker than the original natural chemical free strand. So it's likelihood of breaking is still greater!
Relaxer services using a conditioning lye relaxer between 7 weeks and 6 months (for looser curl patterns) is ideal.
Blow-dry services can be choosen if 1) you are four or five weeks out from your last relaxer service and desire a straight look or 2) your natural curl pattern is a type 1, type 2, or type 3. (curly but not kinky).
If you are a double processed, relaxed and colored, then roller set service is the best service option unless you have a lot of new growth.
For those diehard straight styling clients, you have to maintain the moisture level in the hair to avoid breakage. It is hard for natural oils to run down curly-proned hair. So you are responsible for moisturizing the ends so that they do not break.
Save the "blow in the wind" styling for photo shoots, church, job interviews and other red carpet or black tie events . . .
Moisture product options: Oil sheen, light pommades, butters, natural oils.