Shinintendo said:
About plants bonus I think it's permanent not sure but you can't carry more than 15 so you always got to use them. I used +1 luck flower all the time on Angie.... it's very common on city dungeon outdoors (sunny maps give the best plants, dark give best stones from my testing.)
The herb boni and mali are permanent.
So, better watch out which herbs you are eating.
I've found so much Saffron in the Ashihara guild dungeon, that my main char
has a base Luck of 500 (999 with Technical Style) and all others 350 at lvl 70.
The blue crabs (at guild level 7), sometimes drop Basil (treasure chest), which increases Agility.
I was also able to increase Attack and Def for 3 of my chars without a decrease in other stats.
But "hunting" for herbs can be damn time consuming, so it's not really worth it.
I've found so much Saffron, because it is the most common in Ashihara and I was doing a lot
of guild quests there and checking for herbs everytime.
Checking for stones in plant-oriented dungeons isn't worth the time, because you will only find shards at best.
But checking for herbs in rock-oriented dungeons is still a good idea, because you can find valuable herbs even there.