How recent does your CRC have to be?

If you enter Korea and instead of getting a ELT job immediately, you wait a while doing some other job and later decide to get an ELT job, and CRC is expired, do you need another CRC or since you've been in Korea the whole time since your CRC expired do you not need another CRC?

Most CRC's are good for 6 months. But, having been in Korea the entire time, and assuming you have not traveled outside of Korea for a weekend trip to Japan for example, it may be fine. A lot will depend on what kind of mood the authority is who handles the case. You may be asked to get a Korean CRC.