Aging of Faces

actually I think it's good practice to use layers, masks and compositing wherever possible, since making changes directly to a specific image becomes permanent, and limits any changes you may want to make in the future; the history brush is good for going back and fixing somehitng you want to change, but even then you have to plan ahead by creating history snapshots every so often, etc...
particulalrly in the case of aging a face, where you might notice something afterwards that doesn't look right, you can play with a layer mask without worrying about muddying up the overall face. I also thing that, while the stamp and patch tool are invaluable, they are good for small regions of change and can potentially look a little unrealistic or poorly textured/repetitious if used over large areas.

I have always tried to age a face, but it was hard, and trhis thread has some great tips.
I like the add pores tip, and the composite another face over tip. I am going to try the composite tip. I will take a picture of my dad and use the clone brush and apply some of the stuff to me, and then use a blend mode, and adjust the hue/saturation.