The byproducts of nicotine (Cotinine) can be detected in the blood for up to a 2 weeks. Those that smoke non-light cigarettes or even menthol, could be a little longer after you stop smoking. This is only of concern if you are in a situation where someone else might want to test you for the presence of nicotine or nicotine byproducts in your system.
Otherwise, nicotine is gone within 3-4 days. But it does take awhile for your body to get over the main effects of smoking. Every hour that goes by, your body starts to heal from the effects. Carbon Monoxide levels and your BP begins to lower along with your lungs start to heal and some may start to produce the phlegm as well.
If you stop smoking.. with having only been smoking 2 a day.. then waiting at least 2 even 3 weeks you will be fine. However, if you are tested if anything should come up, that is "smoking" related to the insurance policy. They may not pay any premiums for the policy. Especially if you are listed as a non smoker. So do keep that in mind if you should resume smoking after you test Neg- and get the policy. So to be on the safe side, you need to stop and at least wait 2-3 weeks. If you want to do it in a month, then you will be fine there as well. But that means not even one cigarette, as the byproducts of nicotine (Cotinine) is what they will be testing for.
Just make sure to read the fine print on the policy etc.