Raising skill levels/classes
I've heard through the grapevine that skills can be leveled up to 5 and it would seem it takes a total of 60JP to get any skill to 5 with maximum uses.
The benefit of getting to 5 is maximum effect of passives in the skill chart.
These are the concepts I understand.
On to some questions:
1. Do different skills from different classes provide different passives when combined or is the passive based on class-to-class?
2. Is it possible/advisable to max out all the skills in one class before switching to another? Can you get by maxing out one skill in a class for the skill tree effect (provided they don't offer different effects) and leaving other useful skills at less than five?
3. If you switch from one class to another, can you switch back/can you level skills for previous classes if you have already obtained them?
4. Having not tried changing classes yet, what does the benefit of being the same class as the skills you use actually amount to, in practice?
Thanks in advance to anyone who can give me a little background info here.