Rent control measures, burdensome employment regulations, and excessive administrative requirements exemplify this.

I like to look for board orders, excessive fines for weeds/grass, stop orders, and unsecured premises. 

Can stay in the same budget and use the excess to invest or trade up.

A good rule of thumb is to keep 3-6 months of operating expenses in your rental account as a cushion.Once you’ve got that covered, you can start investing the excess.

Only if a person has a massive active income, providing for significant excess capital yrly and a sizable tax liability does it make any sense to engage in other focus. 

It comes down to having good insurance for protection.I keep around five rentals per LLC, and I am in Jacksonville, FL, where my homes are worth around $250-350k.Having more than ten bank accounts is excessive. 

I looked back at my tax returns when I was doing the conversions from my traditional IRA to my Roth IRA and realized I had converted up to the limit of my standard deduction allowing that amount to be tax free, but the excess above that that I converted each year was at the lowest tax bracket, so while I did convert some money tax free each of those years I DID IN FACT pay more than a few cents in taxes on the amount above the deduction.  

A market like Boston has a long track record of appreciation in excess of inflation/cpi.  

MiThank you, I believe virtually all markets are over valued, but over the long term many (including my primary market) will have appreciation in excess of CPI. 

Find a lawyer and issue a lease violation for other issues such as excessive noise and furniture removal.