Last I checked; Cycles/Superfly needs a complete render before it can denoise the image. Can't denoise till you have a noisy image to begin with. If you are worried about drive life for your main ssd I would suggest you use a second drive to store Poser's and any other images you will be post working on as denoise is only postwork on a finished image. You will never have the first image not happen if you expect the second one.