An idea kept safe too long eventually belongs to someone willing to risk theirs.

Ideas are not scarce and are rarely unique. Holding one back until conditions are perfect usually means watching someone else, with a similar idea and less caution, do it first. What they had was not a better idea but a willingness to expose it.

If you are protecting something, ask what you are protecting it from. Usually the answer is embarrassment. Weigh that against the cost of having held it until it stopped being yours.