Shaving in your headshot session, to beard or not to beard?
It is perfectly acceptable to trim and shave during most headshot sessions. Check with your photographer if you are in doubt, and ensure you bring the right things for the job (dont forget a towel if wet shaving)
Always consider what the varied beard/stubble/clean shaven says about you and your casting. There is no point just growing a beard for headshots if it goes against what you will be cast in, keep in mind it could use up valuable shoot time and you may never use those shots.