Overall, it can be a profitable business, but most people get into it to become an investor and 99 percent fail right away because they don't know the slightest thing about repair costs, talking to sellers, and are only in it for the money and not to help people.

Your first concerns should be your operating procedures and insurance.  

Keep in mind you need to account for soft-expenses as well such as Vacancy/Turnover, Maintenance/Repair, and Capital Expenses.

In 2020 I bought my first house 3 bedroom 1 bathroom and a 2 car detached garage for $175,000 and put a 10k downpayment on it and interest rate was 3.5%, in 2023 I decided to rent it out for $1350 mortage was $1106.62, in 2024 we raised the rent to $1450 and our mortage currently is $1144.76- I never put into account repair expenses, Capex, vacency until I read on rental investment properies book.

While currently unrented, the duplex may serve as temporary housing for tenants from a nearby commercial property I also own, which requires repairs.

If they are 40-50 years old then potentially it would be more expensive to maintain/repair them.

I added value to the deal by initiating cosmetic repairs to make the units rent-ready while preparing for more extensive renovations.

I added value to the deal by completing quick cosmetic repairs, allowing the property to be rented immediately and generate cash flow while preparing for ADU construction.

The other unit he rented to his daughter and family, they lasted 2 months and caused $5000, in damages to the brand new unit""3 years later over $150,000 of renos, he seems to keep coming to us with repairs after repairs"Sorry, but after her requested moving outlets for appliances, I would have said this isn't going to work. 

If you can own the property and pay a similar amount for a similar lifestyle, it's probably a good decision (assuming you can afford it if it doesn't go perfectly, needs repairs, etc.)With house hacking the rule of thumb is: The more uncomfortable you're willing to live, the better the numbers will be.