For example with heat, the fuel (electric, oil, natural gas, etc) all cost differently. 

Learning the basics of electrical , plumbing , AC , painting etc will help you in this line of business which also save you a lot when you acquire your first home.This is how I got started , maintaining the rentals of my uncle  when I was your age. 

But I was spending a lot of time shopping, making the juice and cleaning up.

If we add a mini split, we will also need to upgrade our electric panel, as it is currently full.

Also, if an older home make sure upgrade the electrical panel too.

Offering port-a-potties, well or cistern for water, and some amount of electrical power and wifi located strategically will be enough at first.

You'll want to do due diligence on the more expensive fixes such as foundation, structure, electrical systems, etc.

They don't upcharge very much, unless things actually need attention, and they offer things like annual gutter cleaning, which you can agree to each year or pass on.

Have you scheduled a cleaner to come in and do a deep clean before you start renting.

Sounds horrible and always so frustrating when you just needed a service to be performed.I had the issue with the electrical inspection for the new pool panel in AZ.