While it's indisputably among the best-of-breed email systems available to any business, small or large, managing a Microsoft Exchange installation in-house also consumes a shocking quantity of resources.
This isn't just in the sense of computing power, and keeping your hardware up to date with your needs and the system requirements for the software; it also requires a vast amount of ongoing attention from the administrators. Whether you're controlling the spam and possible virus attacks that come into the system, staying in touch with the major blacklists to make sure your clients stay off of them, or just plain handling the huge mailboxes kept by those people in your company who simply refuse to delete their email. Ever!
On top of these exceptional circumstances, you have ongoing needs which seem to consume only small amounts of resources, but they need to be done frequently and repeatedly; supporting mobile devices, ensuring the backup plans are followed, monitoring remote connectivity, user complaints about undelivered or missing emails, the list is seemingly endless.
Furthermore, the software is regularly upgraded - often requiring new training, new policies, new licenses, and sometimes entire new hardware - and it all has to be done with absolute minimal interruption in service.
Because when you look at most organizations, you find that their single most critical system is often the email infrastructure - when email is down, people often feel that work cannot proceed in any meaningful way at all, and any interruption is likely to create massive losses in productivity.
If something happens to have gone seriously wrong with the system, and it will be hours or even days to get the system running properly again, you can expect your client to spend the entire time asking "is it fixed yet?" at frequent intervals. Once the problem is fixed, they'll want to know why it happened at all, and why you didn't prevent it from happening in the first place.
The reason most people install an in-house Exchange server usually has something to do with the billable hours involved in getting it running, and sometimes it even accounts for the billable hours in keeping it running smoothly. But the entire process is based in the common engineering mindset of "happy path bias" - nothing will go wrong, and everything will be fine forever.
The reality is that there are always unforeseen circumstances, and sometimes those will mean downtime. But while the client probably understands this, they are almost never accepting of this fact, and expect the system to run flawlessly the entire time. Because the expected performance is nothing short of perfection, over time the client inevitably becomes unhappy with the lack of perfection.
And if you've charged your managed services at a flat rate, all the time you spend supporting the system erodes your profitability until it's inevitably lost altogether.
A much better solution is to take a page from the web hosting community, and accept that the process of running an email server is a special-purpose area of expertise that is best handled by an expert in that particular kind of server.
When you think about it, most companies have their websites hosted at an external company which maintains and supports that web server - because that way, all of the details involved in supporting and maintaining the web server are handled by a specialist who only supports and maintains web servers.
So by moving your client to a hosted Exchange provider, you can solve almost all of the problems that in-house Exchange presents. You'll spend less time trying to provide email perfection (which, of course, you can't), more time pursuing proactive projects with your client, plus your clients will be happier with the service... and with you.
It's also likely, with most providers, that you can earn a monthly affiliate commission for every client you sign up on the service. So while removing all the time, effort, and expense that goes along with in-house Exchange servers - you may also be able to add more to your bottom line.
Hosted providers may also offer other services, including web-based services, specific integration with particular mobile devices, compliance monitoring for regulated industries, and other large-scale enterprise server solutions such as CRM or SCM options.
In the end, using a hosted Exchange provider not only saves you time and trouble along with making more money on your bottom line, but also offers a tremendous opportunity to help your clients move up to the next level in their business - using a service that can grow with them the entire time, while providing high-quality specialty service at a level that few smaller IT Support firms can match.