I'm personally aiming for Warrior/Rogue at endgame, and for that reason, I decided to farm from 30 > 39 increasing the gap each level. I calculated this would give me 30k SP and provide me with more than enough SP to completely max out the necessary Warrior skills up until level 60+. So any extra SP gained could go into the Rogue skill tree.
I plan to 2-3 gap after 40 all the way.
