My parents just got the Nokia Lumia 610, and I've set it up using the same "battery saving" features I have on my N8 - power saver automatically goes on, changed connection from 3G to E, screen dims and locks after 30s, etc etc. However, they do nothing on the phones (they don't browse, download, check email, take photos). I've installed WhatsApp (which they hardly use), which I suspect is draining the battery, because the phone lasts from 6am (charged fully) until about 4pm.
I know its a basic phone, which is perfect for them ("I only need to receive calls and smses!"), but surely the battery should last at least a day, especially if they are barely using it? Are there any other default settings which I could change to help enhance battery life?