Different items to use : Common , Magic , Normal, Sacred and Ancestral are categories that define how good the stats are .
I would not discussed Common and Magic items because its low stats and not very exciting .
Normal , Sacred and Ancestral drop based on your level as you level to max 100
Normal start at 1 and can go to 100 max
Sacred start around level 40 ish to 100 max
Ancestral start around 80 ish to 100 max
Lets switch to a secondary designators called Rare and Legendary
Rare (yellow) item can be Normal (hereby called Rare) , Sacred or Ancestral
Rare item has a fixed 4 stats
Legendary item can be Normal (hereby called Legendary) , Sacred Legendary or Ancestral Legendary .
Any Legendary items will have a fixed 4 stats + a 5th stats that is called legendary aspects / affix
This legendary aspects can be xtracted at the occultist . destroying the item and become an Aspect that can be imprinted back to similar Rare items thereby making the Rare items a Legendary / Sacred Legendary or Ancestral Legendary .
The rules are same categories aspect can be imprinted to same categories Rare .
So you can not extract a Legendary aspects from a Sacred Legendary and imprint to an Ancestral Rare . You need to find the same aspects from a Legendary Ancestrals to imprint Ancestral Rare .
The Legendary any categories items now inherit the 5th stats from the aspects .
So Rare will turn to Legendary
Sacred Rare will turn to Sacred Legendary
Ancestral Rare will turn to Ancestral Legendary
There is also another way to imprint rare items using the Codex of Power that you get from completing a dungeon .
Advantage of codex is you can use the codex multiple times and not have to find another similar categories legendary drop and u can use the same codex to regular / Sacred or Ancestral items turning it to the appropriate Legendary items
Disadvantage is codex will always rolled with lowest range of the aspects say if the aspect said " Meteor damage at (x-y) %" , The codex will give you x % .
While if you get the same aspect from a Legendary drop , u might get y % ( max range value)
Obviously if the codex has a fixed value , you dont need to find a similar categories Legendary drop
Last but not least there is a Unique items with the same categories : Unique, Sacred Unique and Ancestral Unique
Unique items can be very powerful but you can not extract any aspects from it . You just use it as is
So once you reach max level and max paragons , you want to equipped all your item slots with Ancestral Legendaries and or Ancestral Uniques with the right stats for your build
Note that the end game items Ancestral Legendaries unlike Primals in D3 does not rolled with perfect stats , so you will have plenty of times to grind your gg Ancestral Legendary and Ancestral Uniques
Not having set items are one of the best decisions about the D4 itemization so far. Not because having set items are guaranteed to be bad (just very very likely). But at least not having set items around, reduces the potential damage Blizzard could do.
Just the same repetition from start to finish. The codex really is a weird addition. Seems like Blizzard got scared it might take more than 2 days to get geared in this game, so lets remove the items concept from items.