I don't have "dormant customers." My clients are people, and my approach to maintaining relationships with them is a simple, old-fashioned one. The most innovative "strategy" I've implemented is a simple, hands-on one: I give my clients a free, annual roof inspection for the first five years after we install a new roof.
The process is straightforward. Once the job is done and the client is happy, I tell them that I'll be back every year for the next five years to do a free roof check-up. I'll send them a reminder card every year. I'll get on the roof, check for any minor issues, and make sure everything looks good. This isn't just about finding problems. It's a way to show them that I stand by my work and that I'm in it for the long haul.
The outcome of that has been a huge surprise. The "dormant" clients responded with a lot of enthusiasm. Most contractors disappear after the check clears. When a business owner comes back every year for five years to make sure the work is solid, it builds a huge amount of trust. It tells the client that you're a person they can count on.
My advice to other business owners is to stop looking for a corporate "solution" to your problems. The best way to "maintain relationships" is to be a person who is committed to a simple, hands-on solution. The best "strategy" is a simple, human one. The most valuable thing you can do for your business is to be a person who is committed to a simple, hands-on solution.