When to use a Data Erasing App? Before A Reset or After?

[Android Central Question]

I've read many tutorials on how to erase everything from your phone permanently. Most say Encrypt > Factory Reset > Add some dummy data > then use a data delete App on the dummy data.

But what about using a data erasing app BEFORE the factory reset? Would that be okay? better? Make a difference? I'm talking about data erasing apps like Secure Wipe or Secure Eraser.

 

[Tim1954]

Best way to erase data is to put a drill through the device, then run over it with your car....

 

[Pcrcol]

^ I need to resell the phone, so I can not destroy it.