A record 4 million people left their jobs in April, sparked by confidence they could get a better one elsewhere, and the rebounding U.S. economy has posted record numbers of job openings in recent months.

Hiring experts predict the tight labor market, where there are more job openings than the right people to fill them, could continue through the fall, giving workers more leverage with current and prospective employers. Workers may be "pleasantly surprised to see there are so many job opportunities springing up now," says Career Contessa coach Ginny Cheng.

CNBC Make It spoke with recruiting experts about what workers should think about before they quit their job, as they give their notice and during their exit to make for a smooth transition.

Before quitting

With leaders paying close attention to recruitment and retention, Cheng says workers may be in a good position to leverage the current moment to negotiate for better work accommodations or a promotion.

Think about what you really want out of your job that you're not getting, Cheng says, like the ability to take on bigger projects or keeping a more flexible work schedule. Then, have a conversation with your manager about how to move closer to those goals. "Maybe you're currently happy and enjoying your role, so the question is thinking in the next two years — how might it evolve?" Cheng says.

If you agree to take on new responsibilities or transition the scope of your job, you can open the discussion of a pay raise or promotion along with it, Cheng says.

Plan ahead

If your current employer can't give you what you want, it may be time to turn elsewhere so long as you're clear on your long-term goals. Now's the time to be choosy about your next job, says Brianne Thomas, head of recruiting at the hiring software company Jobvite.

"Don't run away from something, but run toward something you're excited about," she says. Employers are pulling out all the stops like hiring bonuses or extra perks, Thomas says, so do your due diligence to make sure the scope of a new job will be appealing beyond the current moment. For example, will it allow you to enter a new industry, or become a manager? Are hiring managers scrambling to fill roles because of attrition, or are they supportive of keeping people at the company long-term?

"There's so much opportunity out there," Thomas says, "so it's a good time to be super thoughtful and wait out for a company, culture and role that's going to be a good longer-term fit."

After working non-stop during a global health crisis, some workers are quitting to take a break before finding a new one. If this is the case, career coach and resume writer Chelsea Jay advises having a timeline for when you'll pick up the work search again, and a story of how you'll pitch yourself and your time off to prospective employers.

Even if your break is to travel and spend time with family, for example, know that future hiring managers may want to hear how that time off helped you re-enter the workforce recharged and with renewed focus on certain career goals.

Two weeks' notice is still standard, but there are exceptions

Even in the best work environment, handing in your resignation can feel awkward. Jay says to lead with honesty — "I've enjoyed working with you, but this is an opportunity I can't pass up" — and name the top three things the new job is offering you that your old one can't.

If you're taking a break from the workforce altogether, Jay says to lean on your personal values as your reasons for leaving. For example, maybe the pandemic allowed you time to reprioritize your health and wellbeing, or circumstances motivated you to go full-time into your passion project.

Career experts recommend giving at least two weeks' notice before leaving your job, the idea being that you'll help with the transition and your employer can start to look for a replacement.

But there are exceptions, Jay says: "If you're in a position that threatens your physical, mental or emotional wellbeing and you need to leave sooner than two weeks, go ahead and do that," she says. "At the end of the day, it may be about self preservation and making sure you're able to walk into the next organization whole."

In some cases, her clients have stayed at a bad job for too long, such that they're drained of their happiness and excitement for the new job by the time they get there. Starting in a new place on a bad note "radiates to everyone," Jay says. In the end, "protect your peace."

Making a smooth transition

While there's undeniably something satisfying about the idea of "rage quitting," or leaving a bad employer quickly, Cheng strongly urges people aim for a smooth exit from a company. You never know if your old coworker could become your future boss or client, she says.

Keep track of your daily tasks and workflow so your colleagues can take over for a while and to get your replacement up to speed. You may be asked to update or formalize your job description so your manager can begin to post it on job boards. While two weeks' notice is standard for most employees to tie up loose ends, Jay says you may be expected to stay on longer if you're in a more senior role, manage a team or lead bigger projects. Depending on your exit timeline, you might also sit in on preliminary interviews to help hire your replacement.

Then, on your final days, write a letter of recommendation for your peers or managers through email or LinkedIn, and ask they return the favor.

"As you're leaving," Jay says, "keep communications open."

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