How accurate is Android device manager location ?
Android Device Manager doesn't power on the device's GPS to locate the phone.
It just pings it once, which gets a general location via WiFi or cell towers.
It doesn't matter if you're out in the open or indoors, unless the phone already has a GPS lock for some other reason (say, if it was already doing navigation or tracking points), Android Device Manager won't give a perfectly precise location.
Once the device is formatted you are going to loose everything.
Android device manager Accuracy
It is very hard to locate a phone when it comes to tracking.
There are many third party programs.
But they also work on the same way.
Till the time the phone is one the device can be tracked through GPS and when the person switch off the gps and Internet then it is gone.
And if he flash the Custom ROM , then also it is gone.
So I do not think this locater tools are actually accurate.
They just consume your phone data and battery.
I will not say that this one is 100% perfect but you have something.
If you instantly lost your phone and you have a pc near you, then you can try to locate the same.
It is good to test some other programs also.
On Google Play you can find ample of them.
But it is for sure that none of them guarantee you 100% location of the phone you had lost.