any young people go looking for startup jobs hoping to contribute meaningfully and build their skillset. Instead, plenty end up putting in long hours of drudgery. They're hoping for a career launch pad, but what they get is essentially a sweatshop.

How can you avoid this fate and find a startup job that, while demanding, actually advances your career and leaves you enough time to enjoy life and avoid burnout? Mercedes De Luca, Basecamp COO and a tech industry veteran, has a list of red flags to watch out for.

Of course, no one should go into startups expecting a tidy 9-to-5 workday, but sanity should be a part of your world.

“It's almost an unwritten rule that urgency and long hours are associated with startups — that you're trading longer hours now for a bigger payout later,” agrees De Luca. But, she says, simply because the to-do list at a company is long, all the days don't have to be.

“I personally think seven or eight hours of real work per day is more than plenty. The hard part is that most eight-hour days include three or four hours of wasted time spent on meetings and email,” she says.

Here are the warning signs De Luca says startup newbies should watch out for when interviewing:

Midnight emails: “If the HR rep is emailing you at midnight and scheduling interviews for Saturday afternoons, those are red flags you should heed.”

Immediate email responses: “If anyone you email at the company responds immediately, you know they have an always-in-email culture. It's hard to get work done with that mentality, and it usually leaves people catching up at night and on weekends,” she warns.

Negative social media chatter: “If social chatter about your candidate company skews negative on platforms like Twitter, LinkedIn or Glassdoor, pay attention. Reach out to your networks and raise questions in your interview to fact-check your findings,” De Luca advises.

A paid smartphone: “Does the company pay for internet or phone service, provide mobile devices or pay those bills? That might be either a very generous startup (which is somewhat rare) or a company that wants to own your time.”

Vague stock option promises: “Are the stock options described in terms of the number of shares without any context for how many shares are outstanding or how that compares to a percent equity stake?” asks De Luca. “If they're not willing to make sure you understand what you're getting yourself into, there may be other things they're not sharing.”

Average employee tenure: Are people leaving after brief stints?

Hobbies? “Ask people on the interviewing team what they do for fun at night and on weekends,” suggests De Luca. “If you get blank looks, that means trouble.”

Code words: “Fast-paced environment” isn't necessarily bad, but probe further to make sure the company is working hard and working smart. Phrases that “imply playing catch-up with competitors or any war metaphors,” are always worrying, De Luca says.

Lack of interest in who you are: “When the people in the company don't make time to see if you are a good culture fit, that's a pretty big red flag. They should ask you how you like to work and learn how you'd fit in,” insists De Luca.

Besides staying vigilant for these warning signs, De Luca also says that the onus is on the candidate to ask the right questions and figure out if the job is a good fit. Just asking, ‘What's the company culture like here?' doesn't cut it.

“Some better options include: How does your team make decisions? How do you resolve disagreements? Tell me about something exciting the company accomplished recently.”