Ask any self-employed person what they wish they had most, and those who don't answer "more money" will usually answer something like "an extra hour in the day." It's not that hard to buy that extra hour in the day by hiring someone a few hours a week.
Before you start looking, determine exactly what you would like an assistant to do for you. Do you have a spreadsheet that's grown out of control that you would like reorganized? Do you need a proofreader or someone to check for duplicate content issues? Do you have a social media account you'd like managed for an hour a day?
If you do decide to bring on an assistant, generally the easiest way to do it, particularly if it's on a temporary basis, is to hire them as a contractor. Depending on how much you pay them within a calendar year, you may or may not have to send them a 1099. You can download simple contractor contracts to use, or you can have your attorney draw one up at a fairly low cost.
You may be able to "hire" an unpaid intern if you live near a college or university. You have to abide by certain legal obligations to bring on an unpaid intern, and your best bet for determining if this is a real possibility for you is by speaking to someone at your local college or university in a department that's relevant to the work you want done. For example, if you have a big project coming up that will involve significant research on the physical properties of concrete, you could speak with someone in the civil engineering department about the possibility of creating a summer internship.
The real test of whether it's time for a solo practitioner to hire help is whether the desire for more time in the day exceeds the desire for the money you would earn in that time. If that's the case, start clarifying your needs and exploring your options for bringing in an assistant.
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