The Devil is in the Details
The shaving thing is just a minor quibble. I had the same complaint in Horatio Hornblower "Devil and the Duchess" when Hornblower had been confined to a hole in the prison for presumably days, weeks (?) and came out with only a 5 o'clock shadow.
The truth is that shooting schedules do not allow for the natural growth of facial hair according to the storyline and all too often fake beards look like dead ferrets (much as I loved "Gettysburg" the beards were terrible). When Tom Hanks was working on "Castaway" they shot the pre-island and early island shots, stopped while Hanks lost some weight, shot the post-island shots, then stopped again while Hanks lost more weight and got appropriately bearded, etc. Then they filmed the island sequence. A movie can budget for a long shoot schedule. A TV series can not.
The beard issue is just an observation. I assume that in one of those vest pockets is some Swiss Army compact handy-dandy off-world toiletry gizmo with a razor (hey, Sam might want to take care of her legs, right? And we know Teal'c must shave his head
), toothbrush with paste already embedded in the bristles, floss, tiny mirror, etc.
From a writer's POV, they hope we're so entranced with the story that we don't noticed the oddities (so when do SG1 go to the head off-world? and do the Asgard have toilet paper? :rolly2: ) The problem for all film writers is that the audience can now review their product over and over again. A small slip that might have escaped notice on the first viewing becomes apparent on subsequent viewings. Some writers are aware of this, adding scenes to maintain continuity. And of course, many of those scenes get cut.
I just recently saw "New Ground" again (one of my favorite eps) and noticed the care taken to supply the captured SG1 team members with a red dot on the throat where the blood was drawn -- not just at the moment of the needle, but during the rest of that scene. Knowing that the production team is capable of such detail makes it all the more noticable when they skip past something like the shaving issue in "Paradise Lost."