Just in case, you should sign up for insurance.

Literal

By-chance's time [for-のために], insurance [into-には] enter-keep way [subject-が] good [informative-よ].

保険に入る ('to enter insurance') is the idiomatic 'sign up for insurance.' 入っておいた方がいい combines ~ておく (do in advance) + ~た方がいい (should do) for a precautionary recommendation. Note the には emphasizing the 保険 as a specific topic of entry.