I've had my Oura ring for almost 2 weeks, and it's fantastic. I wear it on my left index finger, and I barely know it's there. It seems to hold a single charge for a solid week. I bought it mainly to track my sleep patterns, but I've enjoyed the feedback from everyday uses, too, like working full-time, swimming, showering, Pilates and lifting weights. It wouldn't have been possible without paying special attention to the Oura ring sizing kit. I knew I would only get one shot to make the right choice. Taking a day and 1/2 to wear the plastic ring sizer on a few different fingers made all the difference in my experience. Don't try to guess your size. Oura ring sizing is very different, and the sizing kit was designed for this very reason. I look forward to enjoying my investment for a long time to come. Highly recommend!