How much can smoking change your singing voice?

I am a singer and smoker (1 or 2 packs daily)

I started smoking at 14 or 15 years old, quit for 5 years between ages 18-23, then took it back up again in a period of stress.

I have always considered myself a good singer; these are the effects I have noticed during the past 7 years of smoking (at least):

NEGATIVES:

1. Breath control and breathing issues.
I have trouble sustaining notes the way I used to, even 2 years ago. This is troubling because of course in performance art and music you must be able to sustain notes.

2. Time it takes to 'warm up' increases.
For a long time I would wake up ready to sing.
Now it is about 30-40 minutes of exercises and stretching my vocal chords as well as 'clearing out the phlegm'. Without a warmup period (and being required to perform) I would be potentially embarrassed because I would most likely 'crack up' or not hit notes on pitch.

3. Loss of 'resonance'.
My voice is THINNER than it used to be. It had more body and was a thicker texture... It has thinned considerably. This is not pleasant to listen to always.

POTENTIAL POSITIVES:

1. OK: I do not agree (at least in 7 years smoking time) that the range (lowest note to highest note) is always affected. In my case.. I actually think my range has expanded. However, I sing daily and practice a lot. So I do think most people can extend their low range (if not always the high range) by smoking.

2. I had a very virginal, pure, quite 'pretty' voice originally. I don't find that clear of a voice attractive for much character. I think there is a small amount of smoking one can do that will affect the voice in a 'colored' way that adds a bit of character. Again, I am not a screamer or anything and I don't sing death-metal.. But I do like a bit of character. Unfortunately I worry that 1-2 packs a day pushes this to the extreme..

Summary:

I don't and would NEVER recommend smoking and I would quit if I could right now. Smoking has changed my voice definitely -- whether it has irreparably harmed it I am not certain, but there IS a change... if you are considering smoking PLEASE forget about it!! I feel like a horrible person being a singer who is supposedly good and a closet smoker, so there is a self-esteem issue involved (at least for me).

Take care of yourself. THINK and if you can quit early then please do.