By this time you're 20, you probably have at least 30K in the bank, you own a home, you live for free, you're a business owner, you have your real estate license, you just bought a sweet truck for work, and you have no debt.

@Haixia YuanTake a look at this link. https://en.wikipedia.org/wiki/Pennsylvania_metropolitan_areasIn terms of cash flow, your sweet spot is probably between rank 4 to 8.

The sweet spot may be plexes on adjacent parcels. 

(Being a C- area, you CANNOT count on pro forma appreciation in the sweet bye and bye). 

Many homes in the Seattle area are getting 50-60 offers and buyers are getting sweet-talked into paying $300k+ above asking price and waiving all contingencies after spending a 15 minute time window at the house, because all the slots to view the home get booked up and there isn't an opportunity to even do a pre-inspection even if the buyer wanted to. 

So, at the beginning of Covid, I worked on the sweet sweat equity, improving the house where I could, like painting the exterior, recaulking windows, and looking for air leaks.

With my nicer rentals I am not getting this type of return, but the appreciation has been super sweet though!

Peoples have different degrees of risk tolerance so there is no best way to go about doing things, just find a sweet spot as far as risk/reward that works well for you and your investing goals.Some people choose to sell their properties after awhile to buy new properties (hopefully at below market value) and thus earn instant equity by buying correctly, and it also resets their leverage back to a higher amount thus amplifying their gains. 

C) Equipment: Buy more/bigger/faster washing & drying unitsMix and match till you hit the sweet spot that works for you.

The sweet spot is somewhere in the middle.Thanks so much for the ideas.