You will spend much more than 10 hours per year unless things go spectacularly well.
I was a landlord for a few years: I rented out a single family house in a nice suburb and I had great tenants and positive cashflow from day one! Even so, you still want to go by the place periodically to make sure it's still standing (you can write off the gas/expenses for this since it's business-related travel!). You have to collect rent and make sure the checks don't bounce. I like money in hand, so I don't want checks mailed to me. You need to file paperwork in some cities for annual rental property registration, need to keep records for taxes, there may be some repairs needed. At the very least you'll need to make sure the repairs are done right.
Easily way more than 10 hours/year. I had a friend who both worked for a property management co and who rented out houses for years. His feeling was that unless you had multiple properties, paying the company wasn't worth the lost revenue.
The biggest risk is having a renter who not only doesn't pay, but trashes the place on his way out and has no assets you can get in a lawsuit. It happens, but you can minimize your exposure. In any event, renting property is not something to be entered in to lightly. Don't do it if you heart isn't in it.