What Nyarlko said is not accurate.
Just tacking onto this, there is a fundamental difference between using
/equip and
/equipset. /equip operates under the condition that it will equip that specific item (even if there are duplicates) entirely at random
UNLESS you use a number to specify which bag the duplicate is in.
i.e. If you have 3 different capes on BLU, 2 in inventory, 1 in Mog Wardrobe
Using the below macro
/equip "Rosmerta's Cape" back
will result in a randomly selected cape from either your inventory or Wardrobe.
If you use the below macro
/equip "Rosemerta's cape" back
1
This will tell the macro to only select the cape from your Mog Wardrobe. You can use the numbers 0-4 to specify which bag you are selecting the macro to pick from. 0 = inventory, 1 = wardrobe 1, etc etc.
Now what happens when you have 2 of the same cape in the same bag? You would use /equipset instead, as /equip is not built to identify duplicates inside the same bag.
So if you have 10 BLU capes in your inventory, and 10 different BLU macros that uses each cape, you can select the
exact cape you want to use for that specific macro and it will lock that cape (or any duplicate/aug item) to that slot
so long as you do not remove that piece from the bag you initially selected. All of the capes can be in the same bag, too (I have 4 RNG capes all in wardrobe 3, they always select the right one during macros). This means if you have 2 BLU capes, a ws and melee one, and you remove the melee one and then subsequently put it back into the same bag, the macro is reset and it has no idea which cape to select. Switching them out essentially resets the macro, so it will pick one at random. Every time I bring duplicate capes back into my inventory, I have to reset my macros for each set, so that I'm sure it's choosing the correct cape/augment piece each time.
You can avoid the macro resetting, by always using equipsets, and always put capes and duplicate items in your mog wardrobes and never remove them. This way, you can set your macro once and not have to change it, as long as you don't move the item between bags. If you must use /equip (if you have no more space for /equipset) then make sure you only have 1 of that item in that specific bag, so you can tell the macro where to pull it from.