The purchasing power of their paychecks goes down, down and down.

Often I go in and spray foam insulate as soon as possible which may cost me $7-10,000 but will not only save me oil money but will keep the units more comfortable year round and cooler during the summer keeping tenants electricity costs down for their A/C.

Post crash no one in power wants to be the bad person and raise the rates and that is why they have stayed low since. 

Other than the obvious of older plumbing, electrical, what else should I look out for?

A full conversion is expensive, not only you need an aditional kitchen, you also need asecond HVAC, water heater, plumbing and electrical system.

The BRRRR Method can be a powerful way to scale up your real estate investing. 

Easiest is to simply divide it by the number of people for anything that is variable (eg heat, electricity). 

@Casey Powers couldn't the same be said about apartments or a lot of multi-family properties? 

I let the tenants take care of the electric, gas, and lawn & snow care.

@Marian SmithThe way I see it, this bullish market is from 3 main things.1) absurdly low interest rates, inflating buying power.2) printing 20 trillion dollars of funny money in the past 18 months.3) inflation that likely only just begun because of 1 and 2.