It’s an avalanche of information. 

Late fee is $77.50 and then the rent also is 1.5% after the first five days which take 18% annual and divide it by 365 to get a daily interest rate then multiply 1550 by that. 

What you’re counting on is even a slow rate of appreciation, say equal to barely inflation, called it 2-3% being multiplied by 4 or 5X because you only put down 20-25%.

Gross rent multiplier (GRM) A method that divides the purchase price by the gross annual rents when the property is 100% occupied.

I don't want to have to paint an entire wall (multiplied by the number of walls that have had nails in them) every time a tenant moves out.

@Jonathan Baptiste cool story glad you learned a lot.Now, multiply all that by 300+ tenants and you'll know what the average PMC has to deal with!

Multiply that by 10 total rental buildings, and you can see the premium jump significantly for your overall portfolio ($3k in this scenario). 

Real estate's "gross rent multiplier" is Wall Street's "sales to revenue",  "cap rate" is roughly "P/E ratio".When evaluating markets and investments I tend to start with GRM (or lazily the 1% rule), then attempt to return a cap rate based on assumptions about costs, then I work my way to multiple years of projections (assumptions about inflation, amortization, tax benefits, etc), and if I am partnering with one of my smart friends I have to pull up an IRR (internal rate of return).I also look at regional employment levels, median income to rent ratio in the zip code etc. 

For market pricing, I collect LTR data from BP rent calculator and multiply by 1.5x.

Time is the ultimate multiplier of wealth.