The market — specifically, the forces of supply and demand — determines the rent your property will deliver. It’s like any other service or commodity for sale in a free-market economy. There’s a price people are willing and able to pay, and that’s the rent you’ll be able to charge.
Determining the rent you can charge begins with looking at your market competition. Similar properties will command similar rent prices. Compare the features and amenities of your property with the competition, and you’ll be able to estimate what rent you can reasonably expect.
So how much rent makes a property a good investment? As with other types of investing, we become landlords with the expectation of making money. (I’ve never heard anyone say they rent properties because they just love dealing with tenants!) Perhaps you want to supplement your monthly income. Or your job transfers you and the thought of keeping your property, renting it monthly and having someone else pay down your mortgage appeals to you.