How to Write a Check-In Letter to a Client You Haven't Served in Years

A check-in letter to a dormant client works when it names what you did for them before, explains why you're writing now, and leaves room for them to reach out if their needs have changed. The letter is not a sales pitch and not an apology for the silence. It is a reminder that you exist and that you remember the work.

The difference between a dormant client and a prospect

A prospect is someone who does not know you. A dormant client is someone who has already decided you are competent enough to hire. That distinction matters because it changes what you write.

With a prospect, you are selling. With a dormant client, you are staying present. You are not trying to convince them to work with you again. You are trying to make sure that when their circumstances change and they need help, your name comes to mind before a stranger's does.

This is why the letter must be specific about what you did before. "We handled your 2019 tax return when you sold the property" is not the same as "we worked together a few years ago." The first one proves you remember the actual engagement. The second one could be a mail merge to anyone.

What to include

Name the work you did. Be specific about the matter, the year, or the situation. "We prepared your estate plan in 2018" or "we represented you in the contract dispute with your landlord" or "we handled your business tax return for three years while you were building the practice." This is not bragging. This is proof that you paid attention.

Acknowledge the gap without apologizing. You do not need to say "I'm sorry we haven't talked in five years." You do not need to explain why the work ended. You do need to acknowledge that time has passed. "It's been a few years since we last worked together" is enough. It is honest and it moves the letter forward.

Give them a concrete reason you're writing now. This is the hinge of the letter. It is why you are writing to them today and not last year or next year. The reason must be real and it must be about them, not about you.

Real reasons: A change in tax law that affects their situation. A new service line you added that fits their profile. A regulatory change in their industry. A milestone you know they hit (a business anniversary, a property transaction, a life event they shared with you). An article you read that reminded you of their specific situation.

Not real reasons: You are trying to fill your pipeline. You have a new business development goal. You want to remind them you exist.

The best check-in letters name the reason specifically. "The recent changes to the Section 1031 exchange rules affect the kind of property swap you were considering in 2021" is stronger than "I thought of you when I read about new tax law." The first one tells them why they should care. The second one tells them you sent a form letter.

Leave the door open without asking them to open it. The letter should end with an invitation, not a demand. "If your situation has changed or if you'd like to discuss how this affects your planning, I'm here" works. "Please call me at your earliest convenience" does not. One of them gives them permission to reach out. The other one makes them feel like they owe you a meeting.

What not to do

Do not ask them to leave a review or refer you to someone else. A check-in letter is not a fishing expedition for testimonials or referrals. If they want to refer you, they will. If they want to leave a review, they will. Asking for either one turns a genuine check-in into a solicitation, and it will feel like one to them.

Do not make it long. One page, single-spaced, is the right length. You are reminding them you exist. You are not re-pitching the engagement.

Do not use language that implies they made a mistake by not calling you. "We'd love to work with you again" is fine. "We've missed working with you" is not. One is an invitation. The other one is a guilt trip.

The mechanics

A letter works better than an email for this. An email can feel like spam, even when it is not. A letter feels like someone took the time. If you have a list of dormant clients whose circumstances fit a specific change (a tax law change, a new service line), you can write one letter and mail it to all of them. The letter should still feel personal—specific about what you did for them, not generic about what you do for everyone.

The best time to send a check-in letter is when you have a concrete reason to send it. Do not wait for a slow season or a business development goal. Wait for the moment when you can honestly say, "This change affects the work we did for them" or "This new capability fits their profile." That specificity is what makes the letter work.

If you do not have a concrete reason, do not send the letter yet. Wait until you do.