Estimated number of days I spent smoking, continuously. Everything I’m going to write here is based on a rough assumption. So, let’s begin.
I will assume that I’ve been smoking for 2.5 years. Now 

2.5 years = 30 months.

30 months = 912 days.
I will also assume that each day, I smoked at least 3 cigarettes. So 
1 day = 3 cigarettes.
912 days = 2736 cigarettes.
Now, let’s assume that it takes at least 5 minutes to smoke one cigarette.

1 cigarette = 5 minutes.

2736 cigarette = 13680 minutes.
Alright, now 

60 minutes = 1 hour.

13680 minutes = 228 hours.
And finally 

24 hours = 1 day.

So, 228 hours = 9.5 days.
Wait, there is more. Those 9.5 days are solely dedicated to smoking, it means I didn’t eat, sleep, or did anything other than smoking cigarettes, and neither I consumed a single second to lit the cigarette, but that’s not possible, right?
Let’s add another thing. Suppose, it takes around ~5 seconds to lit the cigarette, and I smoked 2736 cigarettes.
1 cigarette = 5 seconds.
2736 cigarettes = 13680 seconds.
13680 seconds = 3.8 hours.
And, 3.8 hours = 0.158 days.
Now, summing up everything, we get 
9.5 days + 0.158333 days = 9.658 days.
It means I spent 9.658 days (228 hours + 3.8 hours) doing nothing other than smoking and lighting cigarettes.
Another thing which is not hypothetical but could be interesting 
Taking 912 days as a base, 2188.8 cigarettes were smoked in 182.4 days, and 547.2 cigarettes were smoked in 729.6 days.