Here’s my sample for a thank you letter to an employee for years of service.
Dear (employee name),
This month marks your (number of years) anniversary with our company. Thank you for your (number of years) years of dedicated service.
We appreciate your dedication, hard work, and focus. Our company would not be in the position it’s in without the help of precious team members such as yourself.
We understand that you have many other options available to you, and that’s why we are so grateful that you have chosen to remain part of our team.
Thanks again for all the hard work and we hope to continue our great and productive working relationship for many years to come.