I don't want to dwell on the negatives of my experience, so I'll just give some hindsight advice.
1. Never hire anyone hourly. NEVER. Break the work down into smaller tasks, and pay them by the task. Hourly workers will milk the clock. They'll slow down the project in order to compensate for their perception of poor earnings. I was paying $25 per hour, and they burned through my labor budget very quickly, while the project crept along at a glacial pace. The project suddenly had wings when I switched to task based pay, and they earned more. You just cannot pay them until each task is completed to your satisfaction. Don't abuse this leverage, but don't let them get away with half assed work for whole assed pay.
2. Don't let them take on tasks they weren't explicitly hired for. Otherwise, they burrow themselves deeply in the project and it becomes painful to get rid of them when they start milking the clock.
3. Remember to keep well on the contractor side of the law. It's easy to stray into employment territory when working with contractors and day laborers. To learn more, research the difference between a contractor and an employee.
4. Never offer to reimburse a day laborer for supplies they buy. This is an outright invitation to screw you. You buy the supplies and rent any tools required. When they ask for something, ask them to find it on the home depot app and send you screenshots or links to the item. You can find the item in your local home depot by aisle and bay.
5. Don't let them keep you running to home depot for supplies. At the end of each day, consult with each person on the next days tasks, and build a list of items. After they leave for the day, head over to home depot to buy supplies for the next day. You may want to check your list over with someone who knows what's up, so you don't miss anything. If you allow them to send you off to the hardware store multiple times per day, they'll stop the work while you're gone, and you'll be exhausted. Seriously. They're putting you in a mouse wheel and stopping the work while you're running.
6. Don't ignore warning signs. Bad attitude? Goodbye! Consistently later than the start time they committed to? Adios! Not showing up on days they said they would work? Goodbye! Demanding pay for incomplete tasks? Not a chance. Leaving the jobsite a mess? Get rid of them. Smoking in your house? You're fired!
7. Never pay them until the jobsite is cleaned up. They'll leave a mess if you let them. Make it clear that the jobsite must be clean, including tools and supplies put away before they are paid.
8. Don't try to be friends with them. Treat them with respect, but don't tell them about your life. Don't share any details about yourself. Certainly don't discuss what you do for a living or how much you make. I hate to use this classist meme, but it's true: don't get chummy with the help.
9. Fire people regularly. I don't mean randomly fire them. I mean fire them when you see a red flag. Ask them to step aside, negotiate fair compensation for the work they've done so far for the day, pay them and send them packing. Don't refuse to pay them, as that's a recipe for an altercation. Pay them and part ways amicably.
10. Only hire individuals. They'll often offer to bring a friend. Don't do it until you've seen the first guy's work. If you end up firing the first guy, his buddy will probably quit too. Also, two bad apples ruin the rest far more quickly than one.
11. When you find a day laborer who is honest, works quickly, has a good attitude and shows up when they say they will, go out of your way to keep them. This person is rare, but they are invaluable.
12. Never mingle your tools with theirs. Write your name on each of your tools and insist they put your tools away with the rest of your tools before they leave.
13. Insist that they clean your tools and treat your tools with respect. A worker who doesn't clean and stow your tools is disrespectful and should be fired immediately.
I've said so much about things you shouldn't do. Here's a list of things you should do:
1. Provide bottled water, refrigerated if possible. They work hard, and it's inhumane to leave them without water.
2. Provide some prepackaged snacks like granola bars. It helps keep grumpiness at bay, and helps the workers who may not have enough money to buy lunch. Don't be stingy with the snacks.
3. Provide a proper bathroom for them to use. Keep it stocked with toilet paper, paper towels, soap, clorox wipes, and hand sanitizer.
4. Provide any necessary protective equipment. Dust masks are important for any jobsite. If your house was built before 1985, assume it's riddled with lead and asbestos, and provide the proper PPE. You can't force them to wear it, but you must provide it.
5. If your house was built before 1985, test paint for lead, and test insulation and popcorn ceilings for asbestos. If the tests are positive, have the lead or asbestos remediated before starting any other work. If the tests are negative, still provide the necessary PPE they would need if it were positive. If you provide it and they don't use it, that's their liability, not yours.
6. Pay them fairly. Only evil people make others work for starvation wages. Keep in mind the prevailing wage, and the physical toll this work takes on the body. Remember the 3 Ds of economics: if the work is dirty, dangerous or demeaning, the pay should go up commensurate with the level of filth, danger and demeaning nature of the work. Keep in mind these people probably make very little in the winter.
7. Treat them with dignity. They're sentient beings trying to survive. Treat them with kindness, even as you show them the door. After all, your current prosperity could evaporate in a second, and you could find yourself walking in their shoes. Treat them as you'd like to be treated.