Accessories are another...
Often overpriced and a crap-shot if they fit as described, I'm a make your own kind of guy utilizing "My Garage Technologies" business approach.
The soft pannier Medium ALICE packs (rucksacks) worked well enough, but collected dust on the gravel roads and trails like maintenance dollars in a BMW service shop. So what could be attached, sturdy enough and dust free to handle the bouncing around on my Happy Trail frame, and not cause tears if/when the bike does a ditch-dive being cheap to replace?
At first I thought Mermite cans, but they were so big and heavy, plus the locking lid was going to be a pain, so I settled on ammo cans. All shapes and sizes, but I wanted something that would not block the side of my rear turn signal, yet have enough capacity to make it worth mounting.
I used some mortar ammo cans as they gave me the width and depth, plus hung low enough to not be a center of gravity issue over areas unfriendly to high center mass trekking. Three 1/2" U-bolts and rubber strip waterproofing per case and the first dirt road has proven them functional and with minimal vibration.
$65 into it and I think it'll do... I'll let you know.