Magic classes don't have to worry about TP, its only used for the physical classes. Everyone has 1000 TP throughout the entire game...for now atleast, the current plan is that when Shadowbringers comes out TP will be phased out even for physical classes, though we aren't sure on details yet.

Sprint used to take all of your TP and have a higher time limit the more you had, but this was removed alongside an increased cool down so non-mage classes could use it.