The best well wishes are friendly and personal, such as "Congratulations, you deserve it! We will really miss your (insert positive personality trait)." Take a more creative approach by saying, "You've earned the ultimate promotion. Now you can enjoy the fruits of your labor."
If the retiree if a former coworker, it is nice to thank them for something specific they contributed to your success or learning by saying something like, "your determination really motivates me to be the best I can be at my job." In general, new retirees appreciate feeling like they left a lasting impression on the employees of the company to which they have remained loyal.
It is also important to consider the personality of the retiree. Some individuals have been waiting years for retirement and may like hearing something like, "now all you have to focus on is relaxing, having fun, and avoiding everything that resembles work for as long as possible," suggests Greeting-Card-Messages.com. Others, on the other hand, dread feeling unproductive and are uncomfortable not working and contributing to the success of a business. In this case, offer a new perspective, such as "Now you can get going on all of those home improvement projects you have always talked about but never had the time for."