Exactly
I've known smokers who were clean freaks, and whose houses were as spotless as spotless gets, and I've known non-smokers whose houses...well...let's just say they wouldn't appear on Martha Stewart's magazine cover.
BTW...I've only rented an apartment once (just after I was married), but when we moved out of the apartment after buying our house, the custodian came by to give the place the customary once-over (so we could get our security deposit back). Not only didn't he know we smoked, but he didn't know we had a cat, either (a lease violation, that). Nevertheless, he said, "Wow, you guys are CLEAN," and promptly signed the deposit form. Oh, and the walls were white, too...even after more than two years. Of course, I did happen to wash my walls twice a year (fall and spring cleaning), and I also took down the blinds every other month to soak them in a bathtub full of bleach, and I actually knew how to use a bottle of Windex (once a week) on the windows and mirrors, and I kept the wood floors and our rug vacuumed, and...well, you get the point: I CLEANED THE APARTMENT. WELL. And I am by NO ONE'S estimation what would be called a "clean freak."
But I ain't a slob, either. Both smoking AND non-smoking slobs have dirty houses that smell funny, but anybody who needs professional help to properly clean a house is just incompetent.
Regards,
PS: I'm sorry...you might need professional help cleaning a house or apartment if they had once had a dead body decomposing in it for two weeks in July. Other than that... a weekend of elbow grease and some bleach should be able to take care of everything.