If it seems like every other person you know suddenly has a side hustle, it's because a growing number of workers are taking on second gigs for a variety of reasons, whether it's to pay down debt, meet savings goals, or have a little extra cash on hand for leisure spending. As of late last year, 44 million Americans were holding down side gigs, and while it's a trend that's become common across all age groups, it's especially appealing to younger workers.

Of course, the primary benefit of working a side hustle is money, and that's important, because in a new survey from Simple, 60% of millennials with side hustles aren't happy with their earnings from their full-time jobs. But that same set of data reveals that secondary gigs aren't just about the money. Here are some of the other benefits younger workers are reaping.

Young woman holding mug while using laptop

IMAGE SOURCE: GETTY IMAGES.

1. Personal development

Personal development is generally a lifelong process, so the fact that younger workers feel that their side gigs are helping in this regard is a positive thing. An estimated 57% of millennials with side hustles say that extra work has helped them develop and learn things about themselves -- things that might shape their career paths going forward.

2. Essential work skills

There are certain universal skills that can increase your chances of getting hired or promoted, regardless of the industry you work in. And holding down a side hustle is a good way to develop those skills, thereby helping your career on a whole. A good 44% of younger workers with second jobs say it's made them more valuable as employees, which could open the door to untold opportunities down the line.

3. Improved mental health

You'd think that working an extra job would have the potential to negatively impact one's outlook, but thankfully, the opposite seems to be true among younger workers. In fact, 46% of millennials with side hustles say that their added work has improved their mental health. And it makes sense. Having a fulfilling and productive means of spending your free time is a good way to improve your attitude and sense of self-worth.

4. Better organization

Working a side hustle requires a solid sense of time management. After all, you only have so many free hours in a given week, and when you take on a second gig, you're required to not only work it into your schedule, but keep up with life's other responsibilities and social obligations. Thankfully, 45% of younger workers say their side hustles have helped them become more organized. And that's a skill that'll serve them well at their primary jobs, too.

Clearly, there are plenty of good reasons to have a second gig, so if you're eager to jump on the bandwagon, figure out what it is you want to do on the side and how many hours a week you're willing to dedicate to that endeavor. Keep in mind that 83% of younger workers with side hustles spend six to 10 hours per week on those gigs, while 17% spend 11 to 20 hours. When you're first starting out, however, there's nothing wrong with setting aside two or three hours a week for your side hustle and slowly but surely working your way up.

Remember, the last thing you want is for your second gig to become a source of stress in your life, so take all the time you need to figure out what sort of arrangement is right for you.