The Rebbe's guidance on growing older, retirement and moving into a senior home:
Age brings new opportunities. Advancing age brings new opportunities for spiritual growth, uniting body and soul in serving G-d (IK 1174). Reaching old age is a chance to increase in spreading Judaism, with joy (IK 8591). Both youth and old age need G-d's help, and He gives strength in each (IK 3032, 4920).
Retirement is not retiring. Keep serving the public even after formal retirement; experience and leadership remain needed (IK 10296).
A senior home. Moving into a senior home, like every change in life, is guided by Divine Providence and brings a new mission in that place (IK 3982). Don't be discouraged by difficulties there (IK 1648). Maintaining kashrus in a senior home, physical and spiritual, brings great merit (IK 1181).
See also: Health – Old age and caring for elderly parents; Bitachon – Everything happens for a reason (Divine Providence).