I've worked as a concert sound engineer (live sound man) for years (still on call occasionally) and do alot of studio (record production) work now as well. My hearing is mucho importante to me. I didn't wear any protection at gigs (100-115dB continuous for 3+ hrs 3 times a week) for the first year I worked in the concert sound industry. When I stared into the sink that day and said to myself "you know...the running water just doesnt sound like it used to" I thought I was going to cry. I went out and got fitted for Etymotics Research (no url handy) custom plugs at the local hearing aid place. A little pricey at around $200, but the best $200 I've ever spent...bar none.
You can get 15 or 25dB filters (or both and switch them out), but for shooting, don't even bother with the 15's. I put them in when I get out of my car and take them off on the way back. They don't have the skewed frequency response that foam plugs have (foam plugs have more reduction in high frequencies than low, which make speech particularly hard to discern) and are super comfy. They go in and out with a thought and you never know they're there. Combine them with a nice comfy pair of muffs when you're on the line, and you're in great shape.
As a bonus, you can wear them to concerts, or other loud events, still hear a good tonal representation of the material and protect your hearing to boot.
The human ear hasn't had time to evolve protection mechanisms for the world we've created. Normal everyday noise exposure is causing damage, shooting is just off the charts. I doubt many TFL'ers are still using cotton...if you are: <SLAP> WAKE UP!! It doesn't work, and you don't "get used" to loud noises.
- gabe