For most of the time everyday life is composed of a variety of mundane activities that go almost unnoticed and unrecorded. Many of these will follow a regular rhythm or routine that may vary over the life course as personal and family circumstances change. They may also change over a weekly or seasonal cycle. Although individually such activities could be viewed as trivial, collectively these routines and rhythms construct the fabric of all societies, economies and communities. Studying everyday life in the past is hard because few sources record mundane activities in their entirety or over a whole life span. In this paper the diaries of one woman who lived in north Lancashire (UK) from 1928 to 2018 are analysed to chart the changing rhythms and routines of everyday activities over her life course. She began writing a diary at the age of 13 and completed a detailed daily account of her activities every year until shortly before her death. By sampling the extensive run of diaries, I identify the ways in which her activities changed over her life course, and how they fluctuated over weekly and seasonal cycles. I identify seven key life-course stages during which her commitments to employment, housework, caring and leisure activities varied in response to her changing circumstances. The paper uses both quantitative and qualitative evidence from the diaries to illustrate a rarely seen aspect of change over the life course, and relates this evidence to theories of everyday life, including Lefebvre’s work on ‘rhythmanalysis’.