What is a routine question? The focus of this paper is routine questions and time (in years) since a hitherto routine question was last attempted by the solver. The data comes from undergraduate students' work on solving two calculus questions. The data was selected for reporting purposes because it is well documented and because it threw up unexpected outcomes: what was intended to have been routine was not and what was designed as a relatively difficult question was made easier by the way the student tackled earlier work. The data suggests that students may benefit from active reconstruction of past knowledge and making connections between concepts and procedures.