What’s the difference between 어릴 때 and 어렸을 때?

What’s the difference between 아깝다 and 아쉽다?

What’s the difference between 나이가 들다 and 나이가먹다?

What’s the difference between 특이하다 vs 독특하다? Can they both be used interchangeably? Are they both positive words or negative?

I received a message the other day that said “올 한해도 늘 행복하시고 건강하세요.” I understand what the sentence means, but I was wondering why 올 한해도 was used instead of just 올해도. What is the difference between 올 한해도 and 올해도?

What’s the difference between 겁이 나다, 겁을 내다, 겁을 먹다 and 겁에 질리다? Are all of these interchangeable?

What’s the difference between 관란하다 and 어렵다?

I saw something on sns that said “내일이면 벌써 2020년의 마지막 날이네” What does 내일이면 mean in this sentence? I know the participe 면 translates to “if or when,” but I’m confused as to what 내일이면 means as a whole. Why use 내일이면 instead of just using 내일 in this sentence?