Once you start and get used to a smooth head, you'll hate it when you miss a few days and get the hair back. I know I do. I use an open comb DE with feather blades. Aggressive, but I get a great shave. I can only manage the top of my head with SRs. The most important thing to remember is... if you still have both your ears at the end of the shave, you've done a good job!

Take your time, don't rush, and if you're getting a freshly shaven head and the sun is out (doesn't happen too often here in Wales) get some sun cream on!!