I've seen lots of studies that say nicotine is a good habit to kick in early sobriety. I think that what I have read is the most ideal is to kick the two things almost simultaneously but four months in ain't too shabby either. I totally get piling too many things on at once. I mean these are sort of lame parallels but I often have the idea that I am watching too much tv and need to quit that or the computer, etc. But then I am like whoa, one thing at a time.
However, I do think that cigarettes are different because I actually do believe they can be detrimental to your recovery. Nicotine amps up your anxiety. Cigarettes really take a toll on your body. I was a huge smoker and it is a bitch to quit, in a way it is a harder beast than alcohol but in a way it is also much much easier since there is not so much emotional crap to deal with. But you feel so much better pretty quickly after you stop and you don't have drinking to make you slip. I couldn't quit for reasons like lung disease and far off reasons, I had to quit for today reasons, like I will feel better, I won't huff when I walk up the stairs, my skin will look better, I will be less tired, etc. And all those things are so true. And the anxiety thing. Your anxiety/stress level will greatly subside and I think that is why it is ultimately a good idea for people in recovery.
I just had to give up caffeine (well not give up completely but I was living off it so now I am moderating) because of digestive issues. I drank so much coffee and diet soda, it was freakish. And it was actually easy to mostly give up, but caffeine obviously is not nicotine which I think is the most physically addictive substance out there. Immediately I felt so much better. I had so much more energy. I slept less. I woke up more refreshed. All these things I hadn't anticipated. I was just doing this because I had to get more water in my system and stay less dehydrated but it gave me a much needed boost to how I was feeling.
This is my extremely long-winded vote for yes, quit smoking.