I know every lab has different customs on when and how often students meet with the professors. I usually meet with my advisor once a week, and it has been twice a week this summer while I am also involved in a group project (once individually, once in the group).
These past two weeks, I have been really busy with both undergraduate orientation events (since I live in a undergraduate dorm and am in charge of two floors of girls), and graduate orientation events (since this year I am the Orientation Chair in charge of planning those events). We have 160 new Mechanical Engineering grad students joining us this year, so it takes some planning to pull off a bunch of events for them over a week.
So I asked my advisor if I could skip a week of meetings. He had no problem with this, as he is pretty easy-going in general (and honestly, I think he is busy too with beginning-of-the-semester activities).
But I wonder in general - what is the policy for asking to skip meetings? In some labs, there is a weekly meeting with the whole lab, and one student presents each time. In that case, you may only present once every couple months as you rotate through the group. I would hope that in two or three months you would have some results to show - and if you weren't prepared, it's mostly your own fault.
But I think it's entirely reasonable that if you meet every week, sometimes you just won't have anything to show. And honestly, some weeks everything I say during the meeting I only did the day before... you can get a lot done in one day! It's amazing how time slips away from you. If you have a meeting on Tuesdays, for example, the week goes like this: Tuesday you present. Wednesday you slack off because you just had a meeting. Thursday you have class and you work on homework. Friday - well who wants to work on Friday? Make it a lab clean up day! Then Monday - ack! - you have to get some work done to show on Tuesday.
So I don't feel bad about taking last week off. I was busy getting everybody oriented. But what do you do when you have no excuse, you just didn't get any work done to show? Do you ask to skip that week, do you pull out something older you had saved for just such an eventuality, or do you just discuss future goals?