Practice tests provide large mnemonic benefits over restudying, but learners judge practice tests as less effective than restudying. Consequently, learners infrequently utilize testing when controlling their study and often choose to be tested only on well-learned items. In 5 experiments, we examined whether learners’ choices about testing and restudying are effective for improving subsequent memory performance. Learners studied a list of word pairs and chose which items to restudy and which to test. Some of learners’ choices were honored (by assigning those items to the chosen activity) and some of learners’ choices were dishonored (by assigning those items to the opposite study activity). Surprisingly, and in contrast with all work to date on the metacognitive monitoring of testing effects, honoring learners’ testing choices consistently resulted in better memory performance than dishonoring choices. This effect occurred principally because learners often chose to restudy difficult items, and those items did not benefit from testing. The effectiveness of learners’ choices about testing casts the metacognition of testing in a new light: learners may not appreciate the benefits of testing, but they do have an understanding of circumstances in which the benefits of testing are minimal.