You mean the reroll, extra move, and guard? The guard and reroll can be used as long as you have gems to pay for it. Move may be used as long as you have gems to pay for it, but no figure may pay for more movement than it's original movement value (ie: if you 3 base move, can't spend more than 3 gems on a single figure).
So for example, a pirate can move its base 3 and then pay up to 3 gems for 3 more spaces max? So in theory the pirate can move 6 spaces if you pay the max?