Put in new roof, HVAC system, fixed, replaced parts, and refinished all of the hardwood floors, new kitchen. all of it, down to the non-existent 2 x 4s (historic fire in the kitchen, walls were cardboard and rolled paper in lots of places, new hickory cabinets, fixed falling in ceiling/roof for breakfast room, fixed foundation issues, new subfloor in living room, dining room, new stairs. 

If the house has been vacant for 15 years the electric system is the least of your worries.

The only way you'll know the extent is to hire a plumber to evaluate the entire system and be prepared to spend a pretty penny to bring it all up to speed.

Be sure to screen properly and use this as a lesson to improve your systems.

. :-) Same could be said when I was in CS, I was a systems engineer at the time.

Especially if it was listed on the same MLS system as the for sale property. 

You can upload your property to their system and they will call you if they want to place a family in your property. 

Maybe your system of keeping track of conversations you had with your tenants weren't that effective, but you can always try new systems until you find one that you can keep up with and works for you as well. 

Otherwise, the long term Tenant can claim that you are stealing their utilities for the Airbnb.You can do a RUBS system where you figure it by square foot, and divide the bills accordingly. 

And there is no appreciation rate in the world that would have me risk 18 months of the Ontario legislative system.