i was driving today and the radio turned off. it wouldnt turn back on till i shut off the car and turned it back on.

AC was and all other electronics working fine. what caused this ?

its an 06 g35

Caused by terrible quality OEM radios. It'll continue to get worse. Best option is to go aftermarket.

so, i should just wait for the radio to die then buy a different one ?

If you want the problem to stop happening, id just buy an aftermarket now. if you dont mind it doing that for awhile, wait till it dies

try to just disconnect the negative overnight first tho. not that it will definitely solve your problem... but ive seen a lot electrical problems fixed by resetting the negative