Defense is a weird stat. It only matters when you are reasonably equal to your opponent.
When farming weak mobs, your defense is already so high that you "max out" and adding more doesn't help.
When going up against super strong HNMs (like Jorm for example), your defense is so low compared to Jorm's attack that he is maxed out against you. You add some defense and guess what, he is still maxed out, so it does nothing.
But against middle-class mobs where you are in the "sweet spot", adding defense can have a drastic effect. I have read stories about Roc or Simurgh damage going down from 100/hit to 30/hit just by popping some defense food.
Minne is a basical spell going out as pld.
What Valefor.Houppelande is saying is not right @ every point. Since im playing PLD now for about 2 years i effectively noticed dramatically dmg migration just by adding some def.
Formula is like (Attack/Defense)
So if Attacker and target have same att and def modifier will be 1.
For standard Pld a Minne 5 would mean 400-600 def + 60-80 def.
To a mob with same att as pld def before minne, this would mean:
10-15% less dmg taken. Even more if tattacker has less att, and a bit less effect if attacker is stronger.
