promotions, orbs, guild teachers

i was wondering if it makes a difference if you do these things earlier or later in the game. even though you can get a promotion at lev 20 do you get a better bonus on your stats if you wait til you're a higher level? if you pay to have the guild teachers teach you will you get a better stat increase at higher levels? and does it make a difference how many stat points you get when you trade in a few orbs as compared to a large amount of orbs or does it all equal out in the end no matter how you trade them in? the first time playing i did all these things pretty late in the game, but this time i wanted to get some of them earlier to help me out. but if i'll benefit a lot more by waiting then i dont want to lose out. thanks!