This article uses recently digitized samples of apprentices and masters in London and Bristol to quantify the practice of apprenticeship in the late seventeenth century. Apprenticeship appears much more fluid than is traditionally understood. Many apprentices did not complete their terms of indenture; late arrival and early departure from the master's household were widespread. Other apprentices appear to have been absent temporarily, returning to the master shortly before the end of their indenture. Regression analysis indicates that the patterns of presence and absence broadly reflect the resources and external opportunities available to apprentices.