"I have to because my job uses it" aside, why does anyone use a separate client to check their email? What are the benefits to using (for example) Thunderbird to check your email (which, for example, is gmail) rather than just opening a tab in your browser and using gmail itself?
It's not that I'm against email clients, I just see what the benefits are. I use gmail all the time, and tried using both Mail and Thunderbird (I'm on OS X), but couldn't find any particular reason to use the clients vs. just using a web browser and checking gmail itself. Again, not trying to start a flame war; honest question.
I monitor 4 gmail accounts as well as an ISP mail account through Thunderbird. Those accounts are all monitored 24/7 in a single program and on a single screen. I don't have to keep a browser loaded at all times and I don't have to switch tabs to keep track of each account. All of those accounts also have local storage for all emails in case I need to find something when the net is down or the site is down.
In the last year alone, there have been several instances where gmail usage has been very spotty and in some cases completely inaccessible through the web interface for hours or even a day at a time. Not once have I had to deal with this as the IMAP portion of gmail has continued to run in each instance. Sure, there's a chance the IMAP implementation might go down, but the webmail portion won't. I will still have access to my emails through the web interface even if it's not as convenient.
I also find an actual email program to be much quicker, easier and more efficient to use than webmail. To preview an email, all I have to do is click on it and then click on another to preview that one. I don't have to go forward or back in the browser to do this. The email also loads up instantly without a need to transition to another page.
I'm not personally against a web interface for checking email. It just doesn't suit my purposes and uses and a stand alone email client does suit my purposes and uses.