These days, many workers aren't content with their earnings from a single job. In fact, 45% of U.S. employees hold down some sort of side hustle in an effort to boost their income.

That's both a good thing and a bad thing.

First, the positive. Having a side gig can broaden your intellectual horizons, help you boost your skills, give you an income stream to fall back on if something goes awry at your main job, and, of course, help you pad your savings account or give you access to additional spending money.

Man sitting at a desk typing on a laptop.

IMAGE SOURCE: GETTY IMAGES.

On the flip side, holding down a side hustle in conjunction with a full-time job can be mentally and physically draining. And, focusing too much on your side gig could hurt your performance at your main job. In fact, in a survey of 400 small-business owners whose ventures first began as side hustles, international specialist insurer Hiscox found that respondents worked an average of 20 hours a week on their side hustles in addition to the work they did at their full-time jobs.

If you're intent on rocking a side hustle, the one thing you don't want to do is compromise your primary source of income and put yourself at risk of burning out. Here's how to manage a second gig when you already have a full-time role.

1. Set a clear schedule

Even if your hours during the week are mostly committed to your full-time job, it's possible to devote a decent amount of time to your side hustle as well. The key is to get organized by mapping out a clear schedule as to when you'll be doing that added work. Maybe you'll squeeze most of it in after-hours during the week. Or maybe you'll give up most weekends. Make sure you know when you're supposed to be working to avoid falling behind on important tasks, but also, so that you're leaving yourself with some opportunity for downtime.

2. Get a partner

Some side hustles can really only be done solo, but if you're kicking off an actual business, getting a partner to share the load could help in a very big way. In doing so, you'll have someone to pick up the slack during periods when your main job gets very busy. In the aforementioned survey, in fact, 72% of respondents established their side hustles with a partner.

Keep in mind that you and the person you team up with can have different skills. For example, if you're looking to turn your jewelry-making hobby into an income stream, you can be the person who strings those beads into beautiful necklaces, all the while leaving your partner to take care of things like marketing, accounting, and inventory.

3. Have realistic expectations

When your side hustle is still in its fledgling stage, you'll most likely need the income from your main job to make ends meet until that second gig picks up. Be patient, but also, don't drive yourself too crazy in an effort to ramp up. If you're serious about taking your side hustle full-time, focus on building some savings so you have the option to grapple with a decline in income as you dedicate your time to your new venture. But until that happens, remember that you can only do so much, and that it's not worth harming your health to move that business forward.

It's certainly feasible to work full-time and have a side hustle -- many people do it. Just be sure to get organized, consider a partner, and set reasonable goals if you're planning to go this route.