For example in montreal around 2015 we picked up a 22 unit rental, came in removed the bad tenants, renovated, increased rents, stabilized the property, refinanced (pulled the money out + its cash flowing great currently / within the span of 24 months).

All in about a year time span. 

It will span approximately 1,500 km (932 miles) and will link the states of Chiapas, Tabasco, Campeche, Yucatán, and Quintana Roo, with a total of 21 stations.

These examples span 5 turn-overs. 

Not too bad for a few years span. 

I secured 3 different tenant within the span of about 4 months.

And, non-government jobs have limited life spans.

So HVAC units are getting more expensive; whether due to labor or material costs not sure.Life Span:  From my understanding, your HVAC will last about 6-8 years if you let it be. 

This was in a span of just 4 years from when we started investing.

Then the hook ups can be some work to do well (and you will want to replace hoses/lines, clean the dryer vent, maybe test shut offs), so the less you have to do this the better.Plus, in my area appliance repair can easily be 50% the cost of a new appliance so getting a used one that might not have the same life span or require more repairs can be penny wise and pound foolish.