This is very good service given by google systems. if we have a account on gmail, than messages will be important . if gmail box is full than we should delete certain messages . than it will be stored in a separate back up box. it is done only in gmail back up box. it will depend on seize and days of mail to be stored . they will take from 10 rupees to 100 or more .
I have 100 rupees box extra store for gmail messages .i am using this for my storage of messages . tatally it is a good storage of messages in backup gmail box. ifevery one uses this than it will be good for their important messages to be stored.