A service business can be defined as an entity that provides specialized tasks, often related to maintenance or upkeep, directly to the consumer or another business.
The tasks are usually hands-on manual labor (think: gritty work people don't want to do), and they rarely involve the sale of physical products.
Instead, they focus on delivering a combination of expertise, labor, and convenience to meet a specific need.
The beauty of a service business is that if you know what to do and have access to the resources needed, you can be making money tomorrow! It's as simple as printing out flyers and dropping them in letterboxes or putting free ads on Gumtree and Facebook Marketplace.
Whenever I see that someone is even mildly passionate about something that they are really good at, I instantly start to think, "They could do that for a living."
Here are some classic examples.
Car Detailing: Car people can be obsessive over how they clean their cars and how clean they are. Embedded in this enthusiasm is a skill that they could definitely charge people for. They already have the necessary tools too, so it's literally something that they could be earning money for tomorrow.
Yard Maintenance: Yard-proud homeowners always stand out to me as well. If you're the person with the greenest grass and the nicest yard in your neighborhood, where people are constantly complimenting your lawn and gardens, perhaps that's where your days might be better spent. To be at that level, you clearly have a passion for it and have demonstrated the ability beyond doubt. Again, you also have all the necessary tools and equipment already. You could be promoting your availability already; why aren't you?
Pool Cleaner: I don't know if anybody is as passionate about pool cleaning as folks are about their cars and their lawns. But if you own a pool and you've gone to the effort of learning how to keep it clean, then you could charge other people for the convenience of never having to worry about that. If I owned a pool, I would 100% pay for this instead of going to the trouble of learning about it and stocking up on the chemicals and then having to find a safe place to keep them. This is something people just don't want to do.
Handyperson: Perhaps you're no stranger to home renovations and have one-by-one learned all the skills necessary to repaint a house, re-tile the bathroom, or re-whatever it is that you or your significant other deems in need of change to improve and upgrade the house this month. Handyperson for hire is as legitimate of a service business as any and would be super simple to start promoting your abilities and accepting work.
There's another way to look at this too, which is, what are you already doing for work? You've obviously proven your capabilities already. Maybe once upon a time you needed training and valued the security of a predictable workload. But now you're getting older and starting to see the value in setting your own schedule, owning your own time, and being your own boss. If your boss is charging clients $300 for a job you get paid $100 for, the upside for you is obvious. That's somewhat of an oversimplification, and I go into more detail in the math module. But I felt it was important to mention now as well.
Things you probably can't do:
I don't mention plumbing or electrician work in this instance because if that was something you could do, and were qualified to do, you'd probably already be on that path. They're not exactly hobby skills that one picks up on the side. When I talk about service businesses, I'm mainly leaning into things that you could start overnight based on pre-existing skill sets and a bit of local advertisement.
That being said, I think there's a middle ground of things you probably could do, with some time:
Pest control, mobile pet grooming, and window tinting are just a few that come to mind. Neither of these are service businesses that you could start overnight, as each requires specialized training and equipment; and in the case of pest control, official licensing too. But the reason I mention them is to highlight services with a slightly higher barrier to entry. The higher the barrier to entry, the less competition there is. If you're doing yard maintenance, someone else can get into it just as quickly and easily as you did. But if you're tinting windows, there's a much smaller pool of people with the skills necessary to swoop your clients.