When one opportunity is lost, another opportunity soon becomes available.

Alternative form of close only counts in horseshoes

(idiomatic) To avoid revealing one's thoughts, circumstances, or plans.

Alternative form of when one door closes, another opens

Alternative form of when one door closes, another opens

(idiomatic) To attempt to prevent a problem that has already occurred.

One should be on one's toes and alert of one's surroundings if malicious people are around, to ensure that they cannot wreak havoc in one's life.