I don't have kids that are as old as you all but if I knew that they were forgetting something critical I'd remind them pretty much at any age, I think. I don't go out of my way, though, to have natural consequences for everything. And how is continually forgetting going to be improved by this method? I'd rather do things like have them make a check list for various tasks or do other reminder type things to teach them how to manage a busy life.
Maybe I just see it this way because my chronic illness impacts my memory. There is nothing I can do but learn to live and function this way. Continually suffering consequences in my case will not make me remember and instead will cause stress and discouragement. I think that kids also simply lack the capability to manage all these details and as such might be more like me in that regard until their brains are able to handle more.