Basically all the time! Your education is mostly theoretical and especially in social sciences you won’t study how to do a certain job. Also when studying a language like me it’s essential to spend some time in the country not only to improve your language skills, but also to experience the culture.
The most common things that wouldn’t be a problem at home can become very complicated, e.g. going to the doctor, getting someone to repair stuff in your apartment etc. Even if you can prepare many things, and know the language, you will still need help from people.