I have been wearing these bras for years. I love the fit and the comfort. They provide great support for plus size busts with no pressure on the shoulders and back. Front closure is perfect for women with arthritic hands, shoulders or wrists. I am not sure about wearing them for 18 hours, but I often wear them for 12 at work and home. My husband asked me to add another star because he likes them too. I started buying them online because the price it better than in stores.