I have to agree with the aluminum tank comment. Went out diving with a new HP100 and 4 pounds and was way overweight. Looking forward to no weight at all. Gonna sell my two 80's and go with steel only.
I dive up to 36 and my regs have never been cleaned. Just my dedicated nitrox tanks have been o2 cleaned. I had the same concerns about the regs called dris and they confirmed 40 and below they are good as is.