living on a pension; pension life
Refers to the lifestyle or state of living primarily on pension income, often in retirement.
My parents have started living on their pension.
Saving money is essential when living on a pension.
年金 means 'pension' or 'annuity' itself, while 年金生活 refers to the lifestyle of living on that pension.
老後 means 'old age' or 'retirement years' in general, not specifically tied to pension income.
Compound of 年金 (pension) and 生活 (life, living).