I guess it all depends on the person........technique and expertise plays a big part in this.....generally those who are in it just for their own pleasure will climax quicker than others.....so realize that you are not the only one involved...and you will probably last longer.
5 Minutes are maximum i think. Normal people may indulge in it for maximum about 5-10 minutes not more than that. To enhance sexual time you may take generic viagra. One of my friend is using generic viagra and he stays about an hour with his girlfriend.