As you may all know, giffgaff to giffgaff calls are not free once they exceed the one hour limit. Adter one hour, they are being charged. Although, you can redial for free giffgaff to giffgaff calls.
My idea is to put an option on our giffgaff account which lets us end calls after an hour, where we can choode which contacts we want this option for or simply choose "enable for giffgaff contacts only".
I have gone over the one hour limit many times without realising and its good for people who ring a lot.