I straighten my hair almost everyday how long will it grow in two years?

On average your hair grows about half an inch each month. As long as you don't cut your hair, it could grow up to 12 inches in 2 years but strightening your hair every day is damaging and in 2 years the ends would need to come off. I advise that you condition your hair as much as possible and keep heated appliances to a mininum. I know that you probably like your hair to look as perfect as possible, 100% of the time but sacrifices have to be made if you want your hair to look gorgeous and really long. I guess that you have to grow your hair to your desired length before using heated appliances, in order to keep it in tip top condition, at least then you may only need a slight trim rather than a few inches off. This is through personal experience