If your busy working life means you need email management solutions then the Boomerang for Gmail plug-in could be just the ticket for you. The plug-in, which was designed to be used on Firefox, allows users to schedule when their emails are sent and received.
The clever tricks that this plug-in performs could save you a lot of time in your working day, as well as making your communications a lot more efficient. For example, if you have an email that you want to write after work but need to send it inside normal working hours, simply use the application to schedule the email to send at a preferred time. You can also use the application to track important emails and let you know if you haven't gotten a reply after a certain period of time.
This application is an excellent aide for anyone who communicates through email heavily.