Ask your seller how often the lists they promote are up to date. Ideally, you will find a data vendor that tracks and updates contacts constantly—not one which sells previous, useless lists. Not much too long ago, Ash Alhashim wrote a guest post for us advocating for applying Improve-ROI http://buyproxiesreview85285.alltdesign.com/what-does-b2b-marketing-sales-mean-9235201