I have been on the depo for six years and my mom has been on it for 9 years. I love the depo. It really evened out my moods and I have not had a period since the second shot I got.... so pretty much in six years. I have never been calcium deficient but occasionally crave calcium rich foods. I have not had the bypass yet though. I have had the lap band for two years. I have been vitamin d deficient not sure it's was the depo or because I don't go outside often. After five years they suggest bone density scanning because of the possible calcium deficiency, but if you are not low then there is no reason to get a scan. I love my depo. They say you can gain 8 lbs from it. I feel the weight I gained while on it was my poor food choices. Trust me, the depo did not make me eat whole appetizers plus salad, breadsticks, a meal and desert at every restaurant I went to... my fault...