I have used VS exclusively for years, so I use // TODO: comments to keep a list of areas to look at refactoring later, fix (I may be on a different item at that moment and don't want to lose focus), etc. Todo comments have also helped me diagnose a few problems recently, where a past developer had planned on optimizing a function and never go to it, and it was time. It merely helped me see an area of concern that's carried on, where he simply said // TODO: this could be an issue eventually.