It was the third time I lost the cap that I really got pissed off. Because this time, I had no idea how, or where, it had come loose. I strode around my apartment, cursing it, mentally calculating how many of these caps I’d have to buy in the space of a year, given that I’d misplaced the same tiny nub of metal and plastic three times in the last two weeks. I wondered at the decision-making process that led to the removable end cap, because it encapsulates (sorry) everything I don’t like about Jawbone’s otherwise wonderful, recently revived, back-from-the-dead Up activity-tracking bracelet.

Let me back up.

The Yves Behar-designed wristband houses an accelerometer to figure out when you are active and moving, sedentary, or sleeping. Vibrating alerts will wake you in the morning, or after a nap, or notify you when you’ve been inactive for too long. Meanwhile, the smartphone app allows you to enter meals and mood, and after syncing with the bracelet, view how many steps you’ve taken today, or how your sleep went the night before. Much like the Fitbit, it is designed to help you become more aware of your lifestyle, and take steps to make it healthier.