The close-out message matters as much as the welcome one
Most attention goes toward the first message a client gets, and almost none goes toward the last one they receive. That's backward. I used to make this exact mistake myself, giving far more care to the welcome message than the one that closed things out. The close-out message is what a client remembers right before they decide whether to come back or refer someone else to you.
A good close-out does more than say goodbye. It sums up what was done, points to anything the client should keep or reference later, and leaves the door open for future work without sounding like a sales pitch tacked on the end.
Treat this message with the same care as your welcome flow. Write it once, review it the same way, and make sure it goes out reliably at the end of every relationship instead of getting skipped when things wrap up quietly.
Try this today: write a short close-out message you can send at the end of every client relationship, and use it the next time one wraps up.