How Long Does Chemically Straightened Hair Last?

I Have Really Tight, Tight Curly Hair, and iStraighten It Every Dayy Before iGo To School Or Go Out. In The Summer iDont Go Swimming, which iReally Want TO because of my hair. My Hair Looks Nice When its Wet, but once its dry its so uncontrollable and iCant Do Anythiing to My Hair. In My Opinion It Looks Much Better Straight. iM Lookin Into Chemically Straighting it. I Wud Like Some Details On The Process Or Advice On Like How Long It Lasts etc.(: pleez CommEnt Thnk YHu<3