Most of those people will invest off cap rates because that is supposedly based off NOI or income minus expenses.Most times brokers/sellers will completely BS the Income and expenses to get whatever NOI or Cap you want.

Depending on how much expenses you have, roughly 20-25% of your commissions should be set aside for taxes.And, as @Ashish Acharya mentioned, you're supposed to turn this estimated tax money to the IRS 4 times a year. 

Suppose, you have to pay $250k in tax, but over the next 5 years you make $1 million.

Los Angeles is supposed to be the worse area to purchase tax lien properties because there are too many investors in the area with suitcases full of money.

Since I asked him those question yesterday I haven’t heard from him yet and we were supposed to go see the place.

The duplex is a converted single family or there wasn't supposed to be a residential property there?

We all know the 2 inch'ish in diameter size piping doesn't go to large scale buildings and the reservoir feeding the water is supposed to be the clean one to this part of town..... or do we. 

At 10 AM the constable was supposed to show up and I scheduled the locksmith to arrive as well to rekey the locks. 

I guess anything is possible but all you can do is go off datasets and I suppose you can talk yourself out of any deal.

As the property owner, what are we supposed to do to really know whether things like this is permitted?