Lens hood = always, unless in a situation where I have to use the camera's onboard flash, as the lens hood will cause a shadow. Filters, only circular polarizer and once in a while my cross-screen ("star") filter.
I'm a big fan of the lens pouches on the belt. I brought two to DL but my wife shamed me into only wearing one at a time - still, I was able to cram two lenses in there most of the time, and this is just a medium-sized "Zing" pouch. On the last day, I actually left the bag behind entirely, stuffed my Tic-Tac remote shutter release in my pocket, used my new Tamrac belt-mounted battery/memory card wallet and filter wallet, and a single lens pouch. I carried my 28-75mm F2.8, 50mm F1.4, and fisheye 10-17mm - the "essentials"! It worked great, and much of the day I didn't use my Op/Tech neck strap, just kept it on my hand. When I did that, I would use the quick-releases on the strap to make it a small wrist-sized strap, and buckle the unused neck portion around my belt. Batman's utility belt has nothing on me.

The problem is that I'm rather tall & skinny and my butt is not quite big enough to keep my pants up with this much load without the belt cinched
tight and still some tugging occasionally. Suspenders might have helped.