Like is it time based? amount of cash won? amount of tries?
If I recall correctly, it is 2500 exp every 12 minutes spent in the casino.
casino exp needs to be updated, but there was a backend limitation at the time and now we just gotta go through all the slot machines and hook up exp earning to them properly
Casino EXP will, however, change soon.
well i get xp every 15 mins so 12-15 min