Period Tracker

Hi ladies! I have two <a href="">period tracker</a> apps. <a href="">Period Tracker</a> and <a href="">Eve</a>/Glow. I've used <a href="">period tracker</a> much longer therefore it has more information logged in it. However, <a href="">eve</a>/Glow has usually been more exact on the days I'm supposed to start. As of right now, <a href="">period tracker</a> says I'm 3 days late while <a href="">eve</a>/glow both say I'm 1 day late. Which one should I go by?