During graduate recruitment visits the last two weekends, several questions consistently come up. Some of them make sense. Why did we (the grad students), pick GiantU besides the ranking? What is [insert professor] like? Can I live in GiantUTown without a car?
Questions that make less sense to me are things like: Where else did we apply? How long does it generally take to graduate? (This one is a very advisor-dependent question...)
The one question that came up more than I expected was this: does [insert professor] expect you to be in the lab on weekends?
Here's the thing: most professors in my department really don't care which hours you work. In some groups, it is expected that *someone* will be working every weekend. Generally, this is because there's one particular piece of equipment everyone needs to use, and so in order for everyone to get things done efficiently, someone will end up in the lab on the weekend. On the other hand, even for the most hard-core experimentalist, there is always work you can get done without actually being in the lab. Literature searches, data analysis or writing up results all immediately leap to mind.
I don't understand professors (at least in engineering, where we don't generally need to keep things alive) who expect their students to keep specific minimum hours. I can be in the office for 14 hours a day, but somewhere after the 11th hour, I stop being very productive. If I'm working on multiple projects, I can often work for longer. But I can only work continuously on the same problem so long.
Do you have a productivity threshold for a single task, or can you just work almost indefinitely on a problem, given enough food and caffeine?