If you have external email accounts attached to GMAIL the frequency of checks by GMAIL varies according to the volume of emails received.
Gmail POP3 checker is a user script you can download and install into both Chrome and Firefox, which allows you to change the settings in Gmail so that your external accounts POP3 faster than the default of once every hour.
The default settings consist of POP3 requests once every 12 minutes, with the option to manually click on the countdown to POP3 immediately. To unlock the additional settings with the ability to POP3 as few as once every 3 minutes a donation of a nominal amount is requested. If you don’t wish to donate, the default settings will still enable you to POP3 faster than the POP3 default feature in Gmail.
