I use Thayer's WH products as well, for about 2 years...often I will use just that and nothing else (no balm, no nothing)...it does a great job for me all by itself; as far as your health is concerned, I'm not sure what you are afraid would happen to you, but in the last 2 years I haven't had any infections from nicks or anything of the like. No other illnesses to speak of - i think I had a cold for 4 days...pretty good track record!
The disinfectant attribute of the alcohol content in after shaves is questioned by many authorities. Due to it's low percentage (30%-50% wheras percentages higher than 70% would be needed) it's not as effective as it mght feel like.
Use witch hazel and don't share your razor.
I was talking about this with a co-worker this evening. Can someone point to a discussion on what exactly Witch Hazel does? What is the difference between a splash and a balm AS? What is AS supposed to do? Other than disinfecting? I understand the smell aspect, but what else is it supposed to do? And what are the tradeoffs between splash and balm. I use WH my wife happened to have around and Nivea aftershave, but I couldn't explain to him why I did so. He is looking into buying an AS that comes in a balm and a splash, but I couldn't give him any real advice. Thanks!