The use of flat irons
Yes professional is better, but should only be used twice a week, everyday can cause severe damage to the hair such as breakage, no shine, etc.
In conjunction with using a flat iron one should use a heat protector, whether it be a spray or silicone.
Also we should remember to do a treatment at least once a week on our hair when using a flat iron just for that extra protection and maintaining good health for our hair.
So whether you are using a GHD or a Safeway from Clicks always treat your hair with care. :)