non-stacking attributes

First off, want to say you guys are doing a awesome job on the site. Loads on info for everyone, really appreciated. Been registered for a long time, but never posted anything.

I am just wondering about when it says non-stacking. I know how it works for runes, but what about armors? I dont remember the name of the armor and I'm at work, but there is one for warriors that says it lowers the damage received and it's non stacking.

The way I understand it, if it's not stacking, it's not worth to buy the whole set. Might as well buy parts of the different armors available and look stupid. Not sure if i make myself clear, sure hope so.

Thanks for the help!

Well. Yeah. That's why people wear the Knight's/Ascalon Boots and then get w/e else for the rest of their armor.The Knight's dmg reduction is global, so even when you only have the boots, dmg is reduced no matter where you're hit. The armor is somewhat ugly, and it's inefficient to get 4 pieces of armor that can do only one thing, when you can get 1 piece that reduces dmg globally, 1 piece that increases KD length on foes, and the other pieces that give + nrg.
Now, sometimes it might be good to get more than one of the same armor for armor's that have +armor against a certain thing, since the + armor mod isn't global. Like, rarely, you'll see some 55 monks running out with all tattoos except with a Saintly/Wanderer's chest piece, since you have a 33% chance to get hit in the chest, and they go out there and farm against the avicara, who have a potential to pwn with their Ignite Arrows fire dmg.

But, if it says (non-stacking) next to it on armor mods like the Knight's Boots, then it usually means it's not worth buying all of them. Are there any other armor mods that have the (non-stacking) note next to them?

Thanks alot! Again I find an answer to my questions on GW guru!

Also thanks. I was wondering the same after reading about the hit locations and such.