It's recommended that you wait until you miss your period for the highest accuracy, even with the ones that say you can test 5 days before your period.

It depends on the test and your body! I remember I once took a test a day before my missed period and it came out negative when I in fact was pregnant. Two days after my missed period there was a light, light line. 

Depends on test Hun how sensitive it is x

I would wait. I took four test before and they were all negative. And I was pregnant. There's never a reason not to wait. Gives false hopes or either unnecessarily lets you down. 

took a test a week before AF was due, negative. took another 2 days before AF was due, negative. took it the day after AF didn't show, positive.