I'm a little confused. Wasn't his power such that he could create anything 100% perfectly, 100% of the time? Now it's suddenly saying he can only do so the first time? I'm assuming it means he has a time limit between using the power or something.
Secondly, how does he even know if the crystal has broken and something has gone wrong, if he can't even see the crystal? He won't have the memory of how he was killed, and because he doesn't see the crystal, he doesn't know he was; he'd just proceed to make the same mistakes. Stupid.
Here's a way of using the crystal: Something like a windup clock, where if it reaches the end of it's run, it'll break the crystal; otherwise, so long as he sticks to the schedule of winding up the crystal breaking object, he will be checking on the crystal at the same time and thus seeing if his day went without a hitch.
No crystal? This means he needs to be careful the rest of the day...
Well, this all assumes that the save crystal disappears from its origin point when broken.