Something I wish I knew when applying my Alien Registration Card (now called the Residence Card), was how important the exact spelling and spacing of my name would be for my life in Korea. No hyphens, no irregular spacing, perfectly matching the passport! Case 1 - When getting an 인증서 for personal use, while registering for COVID vaccines, the system wouldn't accept spaces between lastname/firstname, because of course they didnt expect foreigners to be using the service! I'm grateful that my Korean co-workers were able to call the Public Health Center and help me navigate through that. Case 2 - Using Naver account for shopping and payment services for 4 years, one day it suddenly won't let me login. Tried to change password, realised the verification won't go through because my account name was not the same as my ARC name! Once again, rescued y Korean co-workers and their knowledge about the system. Since then, my first recommendation to any new foreigner in my vicinity who comes to me for advice is "make sure your name matches everywhere". Even if its long, even if you dont use half the characters in your name, the system depends on it for security and verificiation! (There's plenty more things i could add here in the "wish I knew" section, but this is the first that came to mind! Cheers!)