QI failures can fall into several categories: scammers who steal money or information, ineffective operators who can blow your Exchange and get the IRS after you, weak QI infrastructures that don't have adequate insurance or safety protocols against outside fraudsters, etc. 

Make sure the space meets local building codes and safety standards.Market Research: Research rental prices in your area to determine how much you can charge for the basement apartment.

It's not just about safety.

I get the safety net for the buyer, but at the same time we cannot sit on that money for up to 3 years.

The cashflows is also really solid and gives you a margin of safety in case there are any repair issues in the future.

However, it's important to consider the liability and safety concerns that come with allowing guests to use a golf cart they don't own.

Focus on markets that have a good thesis behind why they will appreciate and prioritize  this over cash flow.

Avoid risk, which means do inspection and safety audits.

As a solo operator I soon ran into the problem of having too many properties to pursue at a time.....like 100's of them and I figured out that I needed to prioritize my efforts in some way. 

Cost me 5k, the upgrades were not unreasonable, and the electrical work included safety improvements.