depends on the purity of the coke. iv been lucky enough to get coke so strong that one good line had me quite fucked for a good hour and a half which the gram done me almost 6 hours and other times wher iv sniffed a gram in one go and felt very little effect. do you know roughly how strong your coke is?
p.s i mean a few nights before the rave lol not a few hours before it lola nd just like villian said you will always want more when you run out lol