We hear a lot about side hustles these days, and given that 45% of U.S. workers have one, they're clearly pretty popular. In many cases, taking on a second job is a great idea. That side gig can not only help you boost your income, but it can also give you something meaningful to do with your time. And often, the skills you develop in the course of that gig are ones that can position you for a better job in the future. But in some cases, taking on a side hustle may not be the right move for you. Here are a few such scenarios.

1. Your employer prohibits it

Some companies expressly bar employees from working a job on the side. In many cases, this restriction will be limited to the scope of the primary job in question. For example, if you're a full-time web developer, you may be banned from doing that very same work for private clients (or any related work, for that matter), but you can walk dogs or wait tables on the side. Review your employer's policy thoroughly to ensure that by taking on a second gig, you're not putting your main job at risk. And if you clearly don't have permission, don't chance it.

Woman taking notes at desk

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2. You'll make more money excelling at your main job

Many companies offer generous performance bonuses that reward employees for hard work. If such a program exists at your company, it might pay to put in a little extra time at your main job rather than devote hours to a side hustle.

Imagine you stand to collect a $10,000 bonus at year-end for a stellar performance at work, but to snag that cash, you'll probably need to devote another five hours a week to the job. If, during those same five hours, you're only looking at making $100 total from a side hustle, you stand to benefit more financially by devoting the time to your main job.

3. You're already burned out

Some people have no problem working a lot and pushing themselves to do more. But if you're already at the point where you feel that you work too much and are stressed out and unhappy because of it, then a side gig could be just the thing that pushes you over the edge. And that could not only hurt your career, but compromise your mental and physical health.

While working a second gig is a great way to earn extra money -- money you may be desperate for -- in some cases, it's not the smartest move. If you're low on funds, take a look at your budget and find ways to cut back on expenses. That could mean dining out less often, downgrading your cable plan, canceling your gym membership, or even moving to a cheaper home to lower your rent or mortgage costs. It may not be your ideal solution to your financial woes, but if it's not feasible to get a side hustle right now, know that there are other things you can do to get your hands on more money.