The only time aside from overseas that I didn't use hearing protection was as a teamleader in squad+ size trainig exercises. It wasn't to prepare our hearing, but when you have to communicate down a line in order to keep everyone firing when and where they need, it's good to be able to hear.
By no means am I recommending this, but it's what a lot of us did.
"In 1968 for my senior field trip I was sent to RVN"
"It is far more important to be able to hit the target than it is to haggle over who makes a weapon or who pulls a trigger." -Dwight D. Eisenhower