Alex's Law^H^H^H Guess of Phone Run Times

If we assume that the listed talk time for a phone is the amount of time taken to drain the battery completely by making one continuous phone call, and the listed standby time for a phone is the amount of time taken to drain the battery completely with the phone powered on and with radio active, but otherwise idle, we can conclude that:

If you use the phone for half the rated talk time, you will have half the rated standby time available.

e.g. if my phone is rated for 400h (2 weeks) on standby, and 4h of talk time, in practice I can use the phone for a week if I make 2 hours of calls.

This is a useful rule of thumb for sizing up phone manufacturers' ratings, which use preposterously unlikely fringe cases. To remove the deception factor, just cut the rated standby and talk times in half. I'm sure I'm not the first to realise this, but it seemed worth writing down. Of course, it assumes the phone is not used for other functions. If surfing the web or sending text messages strains the phone as much as calling, then those can just be lumped into the talk time pile. If they drain it less or more, then there's some cludge factor involved.