They yield results, but I understand a lot of other people have jobs where they cannot spend so much time on their listings. 

Properties are spending more time on the MLS, sellers are getting more motivated, and there are deals to be had if you know where to look.With fewer buyers in the market, we’re seeing sellers willing to negotiate on price, terms, and even offer incentives like covering closing costs or making repairs.

Yes this method only works if #1 You make more money than you spend#2  You are willing to spend less than you make.#3  it works because people don't have discipline to pay their mortgage beyond the minimum.  

You want to have your financial house in order so you know what you CAN afford and what you SHOULD spend.

The number one mistake that I saw buyers making was jumping right into negotiating (and not very good negotiating at that) without first spending the time to build rapport.

There are a lot of options out there.Some of the most useful items BiggerPockets members have identified are features that save time so they can spend time working on their next property.

Spending on expensive upgrades is not the answer to improve your tenant base in this type of area.Keep the homes habitable, clean, and safe. 

I currently work with investors looking to build their portfolio with single-family, long-term rentals while managing for them on the back end, making is hands-free for the investor to still work their W-2 job and live their everyday lives and spend it with family, hobbies, etc. 

I know how to use the basic features of QBO, as I do my own expense tracking, but my Bookkeeper is needed for the more complex entries (Loans, capital balances, reconciliation, data entry from PM monthly statements.)I spend almost 8k per year in QBO and Bookkeeping costs (Not including my accountant or tax prep.)

On average, you will spend 10% of your income on maintenance per year.