Hmm.. for the dupes there would likely be two ways that could happen. If the duplicate was maintained by my power/concentration it would vanish a while after I stopped maintaining it. However, if it was completely solidified then it would remain and I would have to get rid of it the old fashioned way.

I would probably make it a mix of the two. Simple Duplication(something I am in contact with and isn't too large/complicated/powerful) would likely not need maintained(it would last a great amount of time just from the initial energy input), however, anything that is large/complicated/powerful or that I am not in physical contact with when duplicating or that is a living thing would likely fall apart the moment I stopped focusing/applying energy.

Not sure though if I should be able to duplicate living things. I just applied that so that I could do Shadow Clone Jutsu! That would be so fun in a fight. Though the real me would likely have to be mediating to maintain just one or two, so it wouldn't be cheap like Naruto.