Financially speaking, I had to start saving every penny I could, so my spending habits changed as well and I became very frugal.

I wouldn't necessarily make a habit of it. 

Get in the habit of maintaining your properties and you'll get less maintenance calls. 

Yes, money can provide future freedom and I think we can all look at our own personal habits to see how we are spending time and resources.

So my friend is not really sure if the mold is harmless or harmful. 

Our experience has been that in cases where there has been prolonged smoking by the prior occupants, the only way to rid the most affected areas of the odour and harmful residues accumulated on exposed surfaces is to gut these parts of the property back to the studs.

You will also need to install cabinetry and countertops, and you may want to consider adding a small stove or oven if you plan to do more extensive cooking in the space.Finishes: Finally, you will need to finish the interior of the garage to make it suitable for habitation.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

You will not learn it all in a week, a month, or a year... they key is to make educating yourself a habit that you do not skimp out on.