In my 29 years of reloading, I have never chamfered my 45 brass. I agree - I think over the long haul, you'd be removing too much material.
Cleaning your brass should be the first step after shooting. Then size/de-prime. If you de-prime first, then tumble, you'll have to dig cleaning media out of your primer pockets - which is a pain in the butt. (Been there. Done that.)
You'll get mixed opinions about this: But I clean my primer pockets before every use. Now, I rather doubt that it needs to be done every time, but I'm not going to try to keep track of how many times I've loaded my brass since I last cleaned the primer pocket. So I just do it every time. This is also why I don't use a progressive press.
For the record, I've been loading for 29 years, somewhere in the neighborhood of 30,000+ rounds, and have never had a misfire of any kind. If it works, don't mess with it.
If you ever find yourself in a fair fight, it's because your tactics suck." -- Allen West, quoting Marine 1st Sgt Jim Reinfinger