I am a couple of months into using a silk pillowcase. They work. My face looks less crumpled in the morning and my hair is not so tangled. Last night slept at DP's sans pillow and my face had that awful smooshed-cos-I-was-lying-on-one-side look, with a lovely crease next to my right eye.
Cant wait to get back to my own lovely pillow tonight.
I'm 42 btw. Best £13 I ever spent.