In my limited experience and what I have read, most drives fail due to electronics and laser failure, not drive motor. In theory, you are right; less time=less wear. The problem is that the moving parts are not what fail and the parts that fail are not moving. I still have a few 1X drives that won't quit.
I would have to say your efforts are a false economizing. A new drive is $50 and it is almost certain that you will want something new before you drive fails through normal use. One heavy user said he found his drives failed, on average, at 15,000 hours of burning. That is 10 years at 4 hours a day. Assuming your drive fails due to wear, reducing wear makes no sense. Your drive will probably fail, if at all, due to something other than wear.
If you do the math it really doesn't make sense to transfer to the HD.