it can use 14 days after charge. I am very happy to have this up24.the only problem up24 should more smart that know you act.ion like sleep by itself not by push button.

The software for this up 24 by Jawbone, who makes the world's absolutely best Bluetooth cell phone wireless headset, is an activity monitoring bracelet showing sleep and steps and more and it is absolutely brilliant. The only half point I take off is because you have to press a button when you go to sleep and press a button when you wake - otherwise it won't monitor sleep. When it does the SLEEP chart it is Brilliant!!! It shows both deep sleep the light sleep and the time you're awake in the middle too! It is absolutely brilliant! And it looks good too! :-) I took off half a point because my skin acid melted the rubber into a soft mushy product like I do to the side of the newer rubber used on the Microsoft mice and the rubber on the most will too. The company replace the so fast I was amazed with their service level. I call them Saturday night when I noticed it and took some pictures and they called me back Sunday mid morning and had a replacement off to me so fast it made my head spin! I couldn't ask for better service even if I had a service fantasy of greatness. I recommend this item and now with a third model coming out first the up, now this up 24 and a new one coming very very soon, the price is going down yet again. And 123 ink cartridges. CA has the best price around for sure! :-)