In my county, as long as you don't relocate plumbing or electrical, you don't need a lot of permits, even on a total rehab..The house was $24k, the cheapest that I ever bought a house for.

I am updating the electrical from one to four electrical boxes, my contractor went to get an electrical permit and was denied. 

A class on plumbing or electrical systems or hvac or something related to building trades will serve you well throughout your life.

Follow-through.Here a couple of clauses from our rental agreement you may find helpful:MAINTENANCE OF PREMISES.Landlord will maintain all electrical, plumbing, heating, and other facilities and appliances supplied by Landlord in good working order.Landlord will perform periodic inspections of the premises, no less than once a year, for the purpose of property maintenance and repair.Landlord will notify Tenant in advance of the inspection.

Holding costs to me are things like water, electric, property taxes, insurance, etc while owning the property.

Let's humoristically call it "How to effectively graduate from the School of Hard Knocks University: the soft and hard tracks".Some numbers (rounded):All rents combined, the property is operating at $5000Mortgage/PITI: $4500Common utilities all paid by owner (single electric and gas meters on the entire property): $500Conclusion: as a result of his ongoing house-hack experiment, the income matches the expenses.Milestone complete.

Luckily, I understand electrical outlets and how to safely install them.I hope some of you will learn from our lessons and I hope others will be encouraged by this post.

The three bids that I've received for installing high-efficiency Rheem furnaces in the units have hovered around $8500 all in (run electrical, gas, furnace purchase, ducting, AC coil for later use, AC line to roof, and then soffit installation to hide the ducting).

We redid all the plumbing and electric.

Occupancy numbers can be an issue if you have low recharge rates.Also consider if electric is out you have no water.