Change smoke detector batteries, new thermostat battery, replace furnace filter, look under all sinks, drain water heater once every year, look in the attic.

I make sure led lightbulbs are in all fixtures and smoke detectors have active batteries.

Over and above that you have Toronto and Vancouver which are playing their own game these days.You are far enough removed from the Big Smoke in Peterborough that prices should be moderated somewhat; the converse is that rents will also be somewhat moderated.  

Sometimes a deal can be slightly negative because you're living there as a house hack now that is a different story because you might "know," that when you move out it will be positive or positive after you raise rents and move out (lets say its a fourplex 4 flat for Chicago folks, and 4plex for us west coasters).In this case, it might be lucrative because in this example you control the "move/out," and conversion from negative cashflow to a positive cashflow scenario so the future potential is definitive versus some hope and prayer that you will someday cashflow (smoking hopeium so to speak).I've also seen some buy negatively cashflow properties here in Seattle PNW (pacific northwest) areas even after they move out (its still negatively cashflowing), but the aim was to build ADU or accessory dewelling units in the back and that eventual exit strategy would yield positive cashflow eventually.

Or should i say criminal behavior which doing this and wiring in your money then they go dark on you is of course a criminal act.

Urine, smoke (whichever type) and any other organic compound has to outgas no matter what.

Is it smoke, dead rat, urine?

Smoke detectors, GFCI outlets, handrails, working heat and hot water, etc.

If the sellers were supposed to and didn't, he or she might be just as in the dark as you. 

He's blowing smoke about selling the property, shrug it off and let him vent.