There are different minhagim as to which ’half of the Sefira’ to observe. As it is generally understood that R’ Akiva’s students died over 34 days, we mourn for 34 days, either from the beginning until Lag B’Omer (with the first few days being waived because of Pesach), or from Rosh Chodesh Iyar until Shavuos.
Among the prohibitions during this period is taking a haircut or shaving. The Mishna Berura (493:12) makes an exception for a sandek, mohel and father of a baby having a bris. When Rosh Chodesh falls on a Shabbos, one may shave on Friday in honour of the double special day. When Lag B’Omer falls on a Sunday (like this year), one may shave on the preceding Friday in honour of Shabbos.
When Lag B’Omer falls on a different weekday, one should ideally wait until the morning to shave.
R’ Moshe Feinstein (Igros Moshe OC 2:95) writes that one attending a wedding during the Omer period may only shave if he’d be too embarrassed to go unshaven. Had he been invited before the Sefira, he should have rather kept the other half so as not to have to rely on this leniency!
There are minority opinions that allow those who shave regularly to shave throughout the Omer. (See Nefesh HaRav, p191). R’ Moshe (Igros Moshe OC 4:102), however, only allows one to shave if not doing so will cause him monetary loss. One who feels the need to avail himself of this leniency should perhaps not shave over Bank Holiday weekend.Let us use this period to remind ourselves as to why we are mourning and to always maintain the correct respect for each other, especially for Torah scholars.