As your portfolio grows, you will personally experience all of the horror stories: dealing with drug dealers; BIG damage done by tenants; lawsuits, evictions, etc.

They get involved in drugs, they drink, they don't pay their bills (including their portion of the rent), etc.

Find distressed situations and try to help them alleviate their problem.

Additionally, many do not consume alcohol or drugs for religious or cultural reasons.The above boarding house is setup as a duplex with the "girls" upstairs and the "boys" downstairs.

If it's an open parking lot without gated access then criminals can loiter, deal drugs, etc. and make an easy escape.

Then there is a "Crime/Drug addendum", a "roommate" addendum, Pet addendum, and a few more similar addendums.  

In some cases it could cost more than 20% to sell, meaning the net after a refi would be more than the net after a sale.Of course a IRC Section 1031 would alleviate the Federal tax, but state and local taxes as well as all the other costs of selling would remain.

Drug addicts in parks leave syringes on the ground, and it's unsafe for kids.

an example of why drugs and remodeling do not mix.

Examples are: tenants who party, sell drugs, make too much noise at night, have police called on them regularly, cause problems and generally depress and bully other "good" tenantsSome reasons I can think are:the tenant is on disability and the rent is guaranteedthe tenant is somehow related to the landlordthe landlord is negligentAre there any other other reasons why nuisance tenants are not kicked out?