While I was in the military we had nicknames for everything, including our personal protective gear, our weapons, and our rucksack full of necessities, which we called "full battle rattle" when everything was worn at once. Yes, it did rattle until we taped, tied-down, and adjusted everything to make it as silent as possible. Although hunting is a far cry from actual battle in an actual war zone, I still call my gear "battle rattle." It’s a nostalgic reference that I think is entirely appropriate, and remaining as quiet as possible is every hunter’s challenge.
I admit that I am guilty of buying a product and just taking it hunting before adequately trying it out. I do not recommend this dicey practice at all and it has bitten me before. That is why I always like to wear all of my hunting gear and take it for a hike. You will quickly learn what doesn’t fit and what needs moved or quieted.
I once bought a retractable device advertised as a rangefinder holder that would make it handy to wear my rangefinder right on the shoulder strap of my pack. It was handy, but it was louder than I could have ever imagined. The top and bottom ends had moving parts that were a nightmare to quiet down and I eventually used electrical tape to trap some moving parts in place.
Electrical tape is handy because it stays on when wet but is easy to remove when needed. It also doesn’t hurt that its black color is very subdued. Coincidentally, I also used electrical tape to cover the end of my rifle barrel to keep out moisture and debris.
Another lesson I have learned is to strategically stack items carefully in my pack. I put heavy items close to my back and as high as possible for weight distribution purposes, but I also try to sandwich any potentially noisy items between quieter items. For example, I will put a water bottle or camera between rain gear and a tarp.
Other items that can be noisy are loose ammo, bow string release, sling swivels, hard plastic scope covers, loose items in pockets, half empty water bottles, loose straps on packs, and anything rubbing against plastic buckles and snaps.
It is easy to find out your noise flaws if you take the time to simulate your upcoming hunting conditions by going on actual hikes, climbs, or walks.