iphone backup is very quick, why
i backed up my iphone 20 mins apart and the second time it was less than 3 seconds, why?. I am not sure if I should restore my mphone from the backup file
for fear it did not back up all my content on my phone.
Because the iPhone backup is an incremental backup, backing up only data that has changed. If you perform a backup back-to-back, as you did, the second backup will be extremely quick...nothing has changed.