Most carriers require at least twelve months nicotine-free for non-smoker rates, and many look for two to five years before their best classes. The threshold is set by each carrier and is not standardised.
Quitting is the single largest premium reduction available to most applicants, and the timing rules are worth knowing precisely.
The common thresholds
Twelve months nicotine-free is the most widely reported minimum for non-smoker rates. Preferred and preferred plus classes commonly look for longer — two, three or five years depending on the carrier.
These are carrier-set rather than industry-standard, which is why the same person can be a non-smoker at one insurer and a smoker at another on the same quit date. Manuals are not public, so treat these as practitioner-reported conventions.
The arithmetic is worth doing
Smoker rates commonly run to a multiple of non-smoker rates for the same cover. If your quit date is close to a carrier threshold, waiting a few weeks to apply can be worth more than anything else you could do to the application.
Reconsideration if you already hold a policy
If you were issued at smoker rates and have since quit, most carriers will re-review after the required period. It is never automatic. You have to request it, and you will usually be re-tested.
Nobody sends a letter reminding you, which is why a great many people carry smoker rates for years after quitting. If that is you, it is worth a phone call to whoever wrote the policy.
The full treatment of this topic is on COPD and respiratory.