We report on a wearable digital diary study of 26 participants that explores people's daily authentication behavior across a wide range of targets (phones, PCs, websites, doors, cars, etc.) using a wide range of authenticators (passwords, PINs, physical keys, ID badges, fingerprints, etc.). Our goal is to gain an understanding of how much of a burden different kinds of authentication place on people, so that we can evaluate what kinds of improvements would most benefit them. We found that on average 25% of our participants' authentications employed physical tokens such as car keys, which suggests that token-based authentication, in addition to password authentication, is a worthy area for improvement. We also found that our participants' authentication behavior and opinions about authentication varied greatly, so any particular solution might not please everyone. We observed a surprisingly high (3–12%) false reject rate across many types of authentication. We present the design and implementation of the study itself, since wearable digital diary studies may prove useful for others exploring similar topics of human behavior. Finally, we provide an example use of participants' logs of authentication events as simulation workloads for investigating the possible energy consumption of a "universal authentication" device.