What are the different customs dealing with facial hair? I know that some do not cut or trim due to halachah and kabalah where as some trim. Also some shave using special electric shavers etc. Of people that trim I notice that some shave there neck as well as cheeks. Is this permissible? Also are they using a razor or a electric shaver?
The issue is one of halacha and not just of custom. The source of the prohibition to shave facial hair is the verse in Leviticus (VaYikra) 19, 27, forbidding destruction of the beard. The Talmud (Makkot 21a) understands that only shaving that destroys the beard, that erases it without leaving anything above the skin, is forbidden. Therefore, shaving one’s face with a razor is forbidden; using scissors is not. The Shulchan Aruch (Yoreh Deah 181, 10) makes this same distinction regarding shaving one’s face (as opposed to sideburns. shaving sideburns is forbidden even with scissors even if hair is left above the skin; the hair of the sideburns must be clearly visible even after they are trimmed). Poskim today permit shaving one’s face with most electric shavers because, using a combination of two blades, they act like a scissors leaving above the skin a minute length of facial hair. Included in the prohibition against a razor is shaving opposite the throat (Shulchan Aruch Yoreh Deah 181,11). Lower down on the neck or the back of the neck is not a problem. The Pitchei Teshuva (Yoreh Deah 181,6) cites the custom of the Ari z”l not to shave one’s beard at all. This, however, is not obligatory for all.