Context switching is expensive, and going home for the day is a big context switch.

If it's 5:00 and you have 30 minutes left on something, most likely it'll take something like two hours tomorrow to get back into and finish it.

If you always go home exactly at 5, it means you are either constantly being inefficient and doing the context switch, you are not doing anything late in the afternoon to avoid the context switch, or you are extremely good at both estimating and optimizing your time so all your tasks are quantized within working hours. While things may work out to look like the third case sometimes, I find it hard to believe anyone is that good that it can happen literally every day, which leads me to believe they're often doing one of the other two things.

From the company's perspective an unmotivated 9-5 employee not as good of a hire as one who deeply enjoys the work subject and actively learns about it on their own.

From your perspective reduced job security because you probably don't perform at the level of someone internally motivated.

Even if that is not true there are enough of these sentiments floating around to affect decisions.

EDIT - If you disagree, a well worded comment carries more weight than a downvote and avoiding the discussion.

I have no such expectation, nor did I say people should work in their time off.

I think people need to keep up their education. Learning doesn't stop when you graduate. Your company should be willing to pay for training/courses/conferences, but I also think people that are passionate about things will naturally grow on their own.

At the least, this might mean staying current with news and/or community, especially within your current toolset/ecosystem. As an example, if you don't usually know within at least a week or so that your main language/framework/database/etc has a new release, you're in this category if people I'm talking about.

And to clarify when I say "9-5" I mean the type of person that always has their stuff packed up and is walking out the door by 5:01pm. This tells me either you've stopped in the middle of something, which means instead of staying for 10 or 30 minutes to finish it you will take two hours tomorrow to regain context, or that when you're done something and it's after say, 4 o'clock, you just don't start anything new.

I don't believe in working crazy (or even just 'extra' hours beyond what you're paid for): that leads to burnout and that is bad for literally everybody. I do think it's better to stay longer to finish and not waste time on the context switch of going home, or other days just leave "early" if you are done and can't finish anything further.

Agreed. The biggest problem I find is that day labourers act/talk like they are craftsman and ask for corresponding wages. In other words: wage is not a good filter to separate people out. Craftsman won't work for day labourer wages but day labourers will not only work for craftsman wages -- they'll ask for them.