-다가는 — Precaution

This expression is used to express the speaker's view that if the action in the preceding clause continues, then an adverse result or state of affairs will occur in the future.

If the action in the preceding clause has continued from some time in the past, then the phrases 이렇게, 그렇게, and 저렇게 are often also used.

This expression is usually used to warn or admonish another person.

Details

1. The expression -다가는 is used in negative circumstances. Accordingly, it sounds awkward when used in positive sentences.

그렇게 공부하다가는 시험에 합격할 거예요. ✕

2. Because -다가는 has a hypothetical meaning, the following clause ends in a phrase indicating supposition or conjecture, such as -(으)ㄹ 거예요，-(으)ㄹ 텐데요, -(으)ㄹ지도 몰라요 or -겠어요.

그런 식으로 운전하다가는 사고가 났어요. ✕

3. When speaking hypothetically about the present or something that is going to happen in the future, as in "If something was to occur..."，then the form -았/었다가는 should be used.

내일 발표를 망치다가는 회사에서_ 잘릴지도 몰라요. ✕

Even though the expressions -다 보니, -다 보면 and -다가는 are similar in that the action of the preceding clause is repetitive or continuous, they are different in the following respects.

Kimchi Reader

Used to express the speaker's view that if the action in the first clause happens then a negative result might occur in the future