すればよかったのに

you should have done

→ 為る
phrase Rare #22,344
you should have done Expresses regret or mild reproach that someone did not do something. It can also mean “if only you had done it.”
JA: もっと早く相談すればよかったのに。
EN: You should have asked for advice sooner.

自己紹介すればよかったのに

You should have introduced yourself.

彼は大学に進学すればよかったのに

He should have gone to college.

もっと注意すればよかったのに

You should have been more careful.

電話すればよかったのに

You should have called.