I didn't consider burning luck to help with a disable traps skill. I guess a low level thief would have to burn about that much to get a solid bonus to make him comfortable at disarming a trap (giving him at level one, a +25 to 100% bonus. Although, I probably would have burned three, giving me 15 to 60% bonusfor a total of about 35% to 95% chanch of success). But than again, the thief can heal I think one luck point per level per day of resting so they can afford to spend it a little more liberally. But I still doubt that he can spend 5 points all session long getting those bonuses. It also makes a difference if the game was a one shot game or somewhat of an ongoing game.
Remember that a thief works like this:
1. Luck is applied AFTER the dice are rolled, so a their only needs to 'burn' enough luck to make the check, if they fail the % roll.
2. Thief rolls a luck die [based on level] for each point or luck burned (d3, d4, d5, etc...)
A thief is supposed to burn luck in doing their thief checks. If they are not burning it for that, then they become super fighters, never miss a save, etc...
Yes, but for percentile you get 5 percent per luck pont spent, so when you roll that d3, you get 5 percent X's what you roll, not one percient (i.e. if you roll a 3 on the luck die you get a bonus of 15 percent, not 3 percent).
I don't think a thief is "supposed" to burn his luck only on the thief skills. thief using his luck bonus die on attacks would not make them a super fighter. Why? fighters get a d3, d4, d5 etc for all their attacks without burning luck, plus mighty deed of arms, so a thief burning his luck points to get those bonuses without mighty deed of arms is certinly not super powerful. The idea that the thief is super powerful because he can burn luck to almost fight as well as a fighter (of course, still likely to have worse AC and hps) dosn't make sense. Yes, the thief can use his luck to help make saves if needed, but that comes more into play with avoiding traps and certain monster special attacks such as breath weapon or poison more then with combat as a whole.
Even when I said the thief in my group could use luick to modify an attacker's die roll to avoid getting hit, the thief still died in the first session he played in and was level 2. The thief failed on a search for traps test (that I roll in secret so they don't know if they found it), and was stuck with a poison needle. Yes, luck could have been spent to boos that role, but since the thief had no idea of a trap was there or not, decided not to burn luck on it. Instead, luck was burned to make the save in order to avoid an instat death (not really instant death as the cleric would have 2d6 hours to stave off the death effect with casting of heal, but the party didnt know that). But, even with passing the save thanks to burned luck, the poison still caused paralysis for 2d6 hours as its lesser effect. Meanwhile, another party member triped a fireball trap. Since the thief was paralyzed I ruled no reflex save for half damage was possible and said thief was burned to a crisp. Cleric tried twice to revive the thief but couldnt pass the spell check and the thief also failed the final check because he now had a negitive luck mod from bruning luck thoughout the adventure. Otherwise he would have lived. Burning off luck has its drawbacks for sure.
The thief, just like other classes, is really only supposed to use that luck die for when it really matters. They just can do it more often then other classes because it recharges slowly. The luck of theives and halflings just don't seem to run out as fast as other's luck, but that dosn't mean they should test fate with spending luck points willy nilly.