What catches people off guard is how casual the last-minute process can feel even when big money is involved. In Korea, some landlords act like the renewal is basically done, then suddenly bring up a deposit adjustment or ask you to stamp paperwork the day before. I would confirm rent, deposit, move-out notice terms, and whether the realtor is involved before you show up, otherwise the "small practical stuff" turns into the whole problem.

The part I would pin down early is not only rent or deposit, but whether they expect a fresh 부동산 fee for what is basically a simple renewal. Some offices in Korea treat renewal like five minutes of paperwork, others suddenly act like they are brokering a whole new deal. Getting that answer in Kakao before the signing day can save a very annoying argument.