We have been hosting since 1995, and actually still have 11-12 clients that started with us at that time. All I can suggest is that churn comes as a result of several factors. 1) Businesses changing/going under as part of larger business cycles. These need to be replaced with new customers. 2) Failure to change/update technologies to fit current needs - again, this can be specific to your customer-base - in our case about 25% have very little need for the "latest" but we have to move them along for the sake of the 75% and new customers.. 3) Wanderlust - some people/businesses just like change - better to let serve them exceptionally while you have them, but let them freely and easily move on. In our case, if they continue in business, we are often able to bring about 10-15% back within several years. 4) Pricing - this is hard if you are just attempting to be a volume host. You have to provide a LOT of functionality (perceived at least) and keep your marketing in top-shape. If you become too expensive for your market, then you need to adjust something. Either reset expectations, pricing, or seek another market segment.
There are certainly other factors that I have not touched.
So, I handle churn by keeping very close tabs on what customers leave us in a given calendar year. I take notes, and request the reason for them leaving. This gives inside into whether we simply failed that customer, they were outside our actual target group, or they just shut-down/found no value in our services. I then work with my B2B partners, and my own small team to try to replace every lost customer with 2 more customers in our target segment.
