I have struggled to find an app to help me reduce the 28,000+ contacts on my iPhone through years of replacing phones and lots of duplicated information. DeleteContacts worked for one run when looking for “Exact Duplicates” and seemed to hit a limit of around 705 until it got down to the last 550. I did have to quit and restart DeleteContacts each time after cleaning up duplicates, but it was still way faster then deleting by hand. I tried to move local contacts to my Exchange account but DeleteContacts hanged, I was able to copy/paste all of them, then deleted them from the Local Address Book. I had to clean up the duplicates again and got rid of contacts with no name. My phone favorites had some issues that I had to clean-up and I’m sure I’ll have a few missing contacts that I’ll have to recreate, but for $4 it was worth it to get down to 3,800 contacts (collected over 25 years in case you are wondering). I would suggest to the developer they work with someone on the guide and offering more instructions, there is certainly room for improvements to make this a great app.