The comps should be measured against homes that are similar age, size, and condition.  

Social media age, most are going on the websites that offer real time bidding. 

I have had an interest in passive income from a young age, and my Mom has been a realtor all my life.

Demoing all the plaster and redoing it in sheetrock, depending on the age of the building and the methods of construction used, tends to have its own special problems, The older the building and the methods used to plaster it, the more difficult it is to do a good job.

It is affected by lot size, year built, construction materials, landscaping, roof age, lot location (does it back to a busy road, lake, or another house), updates, etc.

Also are septic systems doomed to fail due to the age of the system.

Basically to have a brand new more desirable and less maintenance and less negative comments on age.

Then some PM charge a service fee every time they send someone to service the property or if they go to inspect the property - in other words, you might get nickel-dime'd with all kinds of other fees, that could easily raise the "PM fee" to 12%+ (we once got charged $45 service fee + $9 per battery to change the smoke detectors batteries at make-ready).Regardless, you need to factor in at least 8% PM cost, even if you self manage (after all your time costs too) as there might be a time when you might want to (or be forced to, like sickness or old age, or desire complete passive participation) to be completely hands-off and you'll need a PM.

Your efforts now will snowball and catapult your real estate career by the time you're my age, so I commend you! 

Age of big ticket items and bones of the house.