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?

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.