It's not from a former smoker, and it doesn't smell damp. 

Guy is ready to move in on completion, full ask, full deposit, no pets, no smokers.

I've not been in redding as long as you (i've been here 4 years) but my impression is that the vast majority of the people I get applying are smokers, exhibit possible signs of being a junkie, are unemployed, have pre-scribed pets, etc. 

I would go with the tenant that isn't a smoker.

My parents talk about how the baby boomer generation going to be a huge failed generation, after all, they where the pot smoker/hippy generation and now they are the respected generation, who - by the way - raised the Millennial generation.  

Not to mention that I believe that by far most of the wear and tear is due to tenants other than mine (cigarette butts, litter, etc- we don't allow smokers in our units). 

If you are renting it to another smoker they likely will not care.

A smoker that disregards a rule the first time, will always continue to disregard smoking rules in the future.

If he is a crack smoker on the value or wants too much, you can move on without even wasting time talking to the ex.

Have rules spelled out beforehand & decide if you want non-smokers in ur house.