I hate to be the dissenting voice, but I try as much as possible not to forward emails from one account to another for quite a few reasons. For example, if you forward support to yourself, and then handle it from your own account, the transaction history then remains in your account, and when you grow and hand the email back to support, they don’t have the full history.
My preferred method is to keep each account separate. I use Google Apps for email, and I create folders for each account to file all of my emails per account. Then there are options.
You can use something like Mac Mail or Outlook to aggregate all of your accounts so you can check / reply to them from one interface.
You can use the ‘delegate’ feature in gmail to delegate access to these accounts to yourself, so that you can manage them all from inside one gmail interface but still keep separate accounts with all of their individual data.
The third and main thing is to think about the way you use email, and what you really want. Setting up strong filters (to say, move all newslettters to a newsletters folder and not your inbox, or move notifications of Infusionsoft forms filled out to their own folder) will keep your inbox clear.
I get hundreds of emails a day across three different brands that I work with, and managing it is critical. The next step is to. make sure you have an easy way to move emails into you task management system and out of email, and others into notes and research (I use Evernote for this) so that you don’t lose data, but don’t clog up a critical communication channel