In most cases, casino chips are only redeemable for cash at the casino where they were obtained. Attempting to cash them in at a different location or on a different date may not be possible.
Your low denomination chips are probably 99.9% safe that they will be accepted. Technically, chips can expire. But there is zero worry with 4-year old Mandalay chips. Next time you are playing at a casino, take the time to look at some of the chips.