In this commentary, Kuhn and Ranger hypothesize that most people are aware that talent does not guarantee success in case one is lazy. This is also true for the performance in achievement tests that depends on, among other factors, achievement potential (ability) and willingness to achieve (test-taking motivation) of the test taker. They add that Goldhammer (this issue) offers a simple solution, both to the problem of motivational differences and the problem of test speededness. His advice consists in simply setting a time limit for each item. This advice is derived from assumptions about the speed-accuracy trade-off subjects have to make when taking a test. Kuhn and Ranger continue, summing up, the relation between motivation and speed or between speed and accuracy is far from simple, and setting a time limit will not resolve the challenge that every test captures both ability and motivation. Overall, the effects of comparing assessments with and without time limits will probably be substantially smaller than in low-stakes testing, where some subjects may exhibit lower motivation, resulting in higher levels of effective speed and, hence, lower effective ability. However, it should be noted that the validity of a test crucially depends on the congruency between the test items and the task that is to be predicted. Time limits might be helpful in case one intends to predict performance under time pressure.