What is a one-sentence summary of the following article?
After an active career, it is normal for a retiree to miss their colleagues and the social aspect of the workplace.  Make sure friends and coworkers have the retiree's contact information and make an effort to keep in touch. The retirement party or the last day of work is a good opportunity to exchange phone numbers, email addresses, and social media profiles. One of the greatest advantages of retired life is the newfound time to pursue activities and hobbies. Make sure the retiree is enjoying their experience by joining them for hiking, art, tennis, a film, or whatever they enjoy.

Summary:
Strive to keep in touch. Join the retiree for activities and hobbies.