How much smoking is bad for you?

Of course any amount of smoking is bad for you. However I smoke a cigeratte with my friends fairy rarely. Maybe about 2-4 cigerettes a month. How bad is this for me? Does it put me significantly at risk for any cancers?

From Mortality in relation to smoking: 50 years’ observations on male British doctors:

Look up figure 4 in the study.

I hear that as a rule of thumb every second you spend smoking brings you 2 seconds closer to death - that is, one extra second closer.