Help understanding fine points of armor type
I think it would be a good idea to start by reading about attributes (aka stats) on the wiki. I’m on my phone so I don’t know how to post a link but there’s one at the top of this page.
Knowing how attributes work will allow you to understand what each armor set does and what they’re good for, and from that how to combine then.
There’s also a page that lists all the ddifferent sets. I can never remember the name but if you search for ‘prefix’ it sends you there.
“Life’s a journey, not a destination.”
There is a wiki page on armor stats, good place to start. Ultimately, I think it’s more dependent on what part of the game you focus on. Like doing teq or temples, I pref to run with some level of vitality and/or toughness. But in dungeons where it all becomes very predictable, many run zerker. Where as with my thief, in most cases I like assassin with a few sets of mixed accessories depending on the situation. But in some situations and/or builds, people may like carrion. Just all depends https://wiki.guildwars2.com/wiki/Equipment_acquisition_by_stats
Are you sure that you are not missunderstanding the mix’n’matching thing? People in GW2 usually use this term in regards to Armor SKINS rather than STATS.