I have a one bedroom rental unit. It seems a lot of renters are not trustworthy. Current renters claimed not to be smokers but that's not the case as I saw him smoke outside. It also seems one of them is smoking in the unit to one degree or another. Odour treatment is only about $500. I wounder how much a risk this poses to the unit? I don't know how often the smoke. It could be once a week for all I know. But I'm concerned. Talking to them will not help as obviously they will deny. All I can do is assume there is some smoking but I can't prove it. Should I tell them to leave? How much could it cost me financially in practice?