6 valid reasons to miss work — and the excuses your boss won't go for, according to career experts

• There are good and bad reasons to miss a workday.
• Career strategists say taking time off to care for your health or for a loved one is acceptable.
• Using a lack of sleep or a missed train as an excuse not to go to work likely won't fly, they said.

There are about 260 workdays in a year. That means many full-time employees are expected to spend about 70% of their time in the office, literally or figuratively.

But there are inevitably days when we need to miss work — for vacation, for personal or family matters, or for some other reason.

While many companies provide their employees an allotment of sick, personal, and vacation days, it can sometimes be hard to tell what constitutes a reasonable excuse for not showing up for work, particularly if it's a last-minute request.

"It needs to be something that helps your employer see why you wouldn't be productive or that the quality of your work would be degraded and lead to problems," Laura Smith-Proulx, an executive-résumé writer and former job recruiter who's coached thousands of employees through layoffs, relocations, promotions, office politics, and other work scenarios, told Insider.

If you're not sure whether you're justified in skipping out on a workday, here are the best reasons for not showing up — and advice for telling your boss.

Good reasons to miss work

1. You've had a traumatic experience

Perhaps one of the toughest situations to navigate at work is when something unexpected and traumatic happens in your personal life, such as the death of a family member or a friend.

Smith-Proulx said employers most likely wouldn't expect an employee to be at their top performance after such an event, so if you need to request time off, it's best to have a conversation with your boss as soon as possible to allow them to make other plans in your absence.

"You can either share details of the event directly or summarize what happened, depending on what you are comfortable discussing and what actually occurred," she added. "It's possible your boss may quickly understand and you can keep the conversation at a high level with minimal detail.

"No matter what arrangement you set up, make your mental and physical health a priority, while checking in with your team or boss as you are able to do so."

2. You're sick, or you've been around someone who's contagious

Any illness that prevents you from doing your job effectively is a good excuse to stay home.

"If your profession requires you to sit at a desk or stand behind a counter and you're not able to handle these conditions due to flu, a kidney stone, pregnancy complication, broken bone, or other severe incident, most employers would excuse you from work duties until you are able to withstand the requirements," Smith-Proulx said.

Being exposed to something contagious, especially if you work in an office or closely with people in person, can also be a reasonable excuse for missing work.

"Even if you aren't feeling unwell, a positive COVID test means you could infect another worker who is more susceptible to severe effects or even the possibility of death," Smith-Proulx said. "In that case, you should steer clear of the workplace until cleared to return to work."

Smith-Proulx recommended notifying your boss quickly, especially if your workplace will need coverage for the day. Then tend to your needs by monitoring your symptoms.

"If you have a contagious illness such as COVID or the flu, contact your doctor for recommendations on when you can safely return to work — and make sure you're communicating with coworkers and supervisors so they can plan around your absence," Smith-Proulx said.

3. You have no means of getting to the office

Smith-Proulx said that a lack of reliable transportation is an excuse she's heard people use for skipping work.

"If your car or transportation source breaks down or roads are impassable due to ice or snow, you can typically expect an employer to understand the circumstances," Smith-Proulx said.

However, she added, don't expect your boss to give you more than one day off for a reason like this — unless it's an extenuating circumstance you've spoken with your boss about, they'll most likely expect you back the next day.

4. You don't have WiFi, or there are other problems with your work environment

Remote workers who depend on the internet or on childcare to do their job might face instances where these things fall through and they can't show up for work at home.

"Some employers will allow you to delay tasks or deadlines if you cannot access WiFi or are not able to complete tasks away from the office," she said.

However, Smith-Proulx added, companies would probably prefer that you find workarounds that allow you to continue your tasks on an interim basis. For example, she said, if you can't access WiFi at home, you may need to call your boss or use another means of communication to contact them.

"Don't rely on sending a passive email," she said, as your message could sit in your boss' inbox for hours.

If you're dealing with a complication at home — perhaps your daycare has fallen through and you need to take care of your children — it's best to set aside time to convey how you'll deal with this issue if it happens again, Smith-Proulx said.

"Most supervisors understand that life happens and you can't control every factor in your home environment, but may also view repeated episodes in a negative light," she said.

5. You need a mental-health day

There might be times when you just need a day to reset, whether it's because you're burned out or you're dealing with something personal.

"We are working in an unprecedented time, and people are working more than ever before, which can lead to a huge amount of stress," Amy Stoldt, the vice president of people and culture at Snappy, an employee-gifting company, told Insider.

Brooks Scott, an executive coach, recommended adopting a personal strategy for asking for time off for mental-health reasons.

"The best way to communicate with your manager that you'll need to miss work is to focus on your relationship with them by connecting your excuse to something you both share," Scott said.

He suggested using the following script: "Both of us need to have a professional relationship where we can be open and honest with each other. Some personal things have come up, and I need to ask for the day off to focus on my mental health. You know I wouldn't be asking unless it was necessary."

Scott added that it's best to use these types of excuses sparingly, wisely, and truthfully.

6. You're dealing with a family situation

Whether it's a child, a spouse, a parent, or a pet who needs you, it's OK to request a day off to be there for loved ones.

"The best way to communicate a family situation with your manager is to share as much about the situation as you are comfortable with, but of course you are not required to do so," Stoldt said.

She added that it can be good to share how much time you might need to take off so you can help manage job expectations. "You can also offer up that you will work with others on the team to assure your manager that someone is designated as your backup while you are away," Stoldt said.

Bad reasons to miss work

Smith-Proulx said the worst excuses for missing work are the ones your boss expects you to have control over, such as being up late or missing the train.

"When you commit to being on the job, it's expected that you will tend to your own sleep schedule or find alternative means of transportation," Smith-Proulx said. "If you find you are regularly missing work for reasons like these, spend time analyzing how long it takes for you to obtain transportation or ensure you're well rested, which should help avoid routine absences."

She suggested admitting what happened and asking if you can make it up by contributing in some other way.

Many employers understand that time off can't always be planned and should be taken, but they still expect their employees to be productive and regularly available for work. Constantly being absent from work, Smith-Proulx said, "can make it difficult for the employer to continue business, and they may need to replace you with a more reliable employee."