Changing thousands of dollars each time should be ok. Even if ask for IC, just provide, since can say is winnings. Keep low profile, change spectacles etc. also go to different casinos, rotate regularly. 2 in sg, one in kl, and a few in Macau, how to track? Unless you are big time criminal, otherwise authorities would not bother if you stay out of trouble.
The problem is must have strong will power not to gamble.
After laundering some money, next step is to buy assets that yield regular high cash dividend. Keep these dividend in banks, while you spend some of the latter batches of undeclared cash. Though try not to be too flashy.
Some also set up small businesses. Sell to yourself some useless and cheap stuff at high prices, paying cash only. Such as mobile phone accessories.