~기 십상이다 (~gi sib-sang-i-da) – easily to be/likely to be/most probably be
This grammar phrase is good to describe situations, facts or statements that are generally known to public or applicable to a general group of people or things.
This phrase is quite similar to ~(은/ㄴ & 을/ㄹ)것 같다 but with a lot more conviction or certainty that this is a fact that most people would know.
~기 십상이다 can be used to describe matters of fact like weather, illnesses, or anything that has got to do with nature or scientific/proven facts.
물을 충분히 마시지 않다면 병나기 십상이야.
If you don’t drink enough water, you will get sick easily.
잠을 일찍 자면 힘이 많이 빼지 않기 십상이야.
If you sleep early, you most likely wouldn’t lose a lot of energy.
어려운 책을 읽으면 이해하지 않기 십상이야.
If you read a difficult book, you would most probably not understand it.