However, it appeared that they were smoking down there and potentially using the lower unit's electricity. 

There were about 200 cigarette butts all over the front porch.

We did have to recarpet one place and the owner just chose to eat that cost (only around $500 - he used cheap carpet), because of cigarette burns on the carpet. 

While 31 y/o has never been evicted, she has smoked in rentals and had a pet who destroyed carpets to the point that damages ate entire deposites.

If it wasn't the govt, I wouldn't put up with it.Tenants will be okay with you coming in to check their smoke detector batteries and check for leaks every 6 months. 

That way, when a tenant moves out, you can just use a roller and paint just halfway up the wall (unless they were smoking in the unit - grrrr). 

Those carbon monoxide/smoke detectors seem to be more prone to problems than a plain smoke detector.

No smoking--(they must sign that they do not smoke, many will say they don't but actually do)No petsClean criminal background checkExcellent rental reference.

Smoke can easily get to those areas that can hold odors.

It needed flooring in 2 rooms, some slight drywall repair, a window removed and replaced with a solid wall, and a fridge, painted and cleaned to get rid of the smoke smell, and some light fixtures.