Go for the ANR early ie from the outset.
I know its more expensive but just wait until you go for an audiogram and you have a wacking great drop in your hearing just at the pitch of the props.
You will start to struggle hearing people who speak in monotone or mumble with any background noise.
Do companys provide? In my experence it is a mixture of both. Ie some companys provide others do not. Or if they do provide they are utter crap.
Personally I have 2 DC H10-13X's why you might ask. The first one had a fault after 2500hours of flying and I couldn't stand flying with a normal headset while it got fixed free of charge. Now I carry two because the FO usually has a crap company set or a none ANR. They then get the second pair and life gets an awful lot easier. Matched impedences on the intercom, little background noise on the intercom, everyone alot less tired.
Its worth it to me to provide another ANR for the FO for the improvment in my working day. Although it doesn't take long for them to justify getting one after flying a few days with me then having to go back to the crap.
BTW had a shot of the new DC's ANR's utter crap. Virtually no passive noise protection. Frame made out of plastic to reduce weight it will break. And for all its light weight etc after 8 hours flying it still gave you sore ears.
If your worried about the price of 9V bats.
I use this company
http://www.battery-force.co.uk and the procells and one box lasts 6 months plus