Ask about things like overtime, time off, hour flexibility, and remote working and see how they respond. I've found these three things to be quite telling, regardless of your personal stance on them.
How often are people working overtime? What are the reasons for working overtime? How much overtime is being worked? How do you prevent the need for overtime from happening again?
How much PTO is available? If it's limited, are sick and vacation days combined or separate? When was the last time a non-management employee (or level to your position) took a week or more off?
How flexible are the working hours? Do people get reprimanded for coming in at 9:15? Is it frowned upon for someone to come in at 10 (if they're getting their work done)?
What's the remote work policy? How often do people work remotely? How many full-time remote workers are there? How often do remote workers get promoted in relation to their peers?
It's rather likely you won't get straight answers for most of these questions, which alone will tell you a lot (you're not just looking at the answers, themselves, but how the person answers them). Limited + combined PTO discourages taking time off. Clock-watching encourages presenteeism and a "turn the lights on in the morning, off at night" culture. Remote friendliness requires certain cultural elements that foster things like communication and breaks down very quickly under certain toxic elements, so even if you choose to be in the office full time, knowing their stance can be a good barometer for culture. Making excuses for overtime (things like "that's just how this industry is") is a huge red flag. Hour flexibility indicates trust in people's ability to do their job and work when they're most productive, instead of some arbitrary time (shift-style work notwithstanding), which indicates more focus on results.
Additionally, look for signs of discomfort when they go to answer these questions. How they answer the question can betray a lot about their trust level in their workers. Also, don't just ask this of the hiring manager, but of any peer-level employees you interview with. Remember, the interview is a two-way street. It's just as much about you assessing the company as the company assessing you.
Tour the office and make note of the environment. If they have the stereotypical "startup" perks like ping pong tables, see how much they're actually used (many times such things are recruitment bait, but people are discouraged from actually using them). Are the desks decorated with fun stuff, or are they sterile? Do the people look comfortable or on edge? Regardless of your position, find the tech people, particularly QA, documentation, production support, infrastructure, and development. These are the ones at the end of the production lines and who see all the nitty-gritty things going on, and the ones most likely to get blamed when things go wrong, even when it's beyond their control.
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