In some areas of law, it is easy for a claimant to leave it too late to sue (in other words, the law provides that cases must be taken within certain time- limits, such as three years).
This time -limit can run against a Claimant even though the claimant is not aware of the damage. However, in general, where the wrong relates to a personal injury (such as one might suffer in a car- accident), the time-limits do not run against you unless you are “aware” of the injury (injuries can sometimes occur which might only become manifest years later).
The difficulty with personal injuries is that the time runs out after a shorter period than in most other claims, namely two years ( for personal injuries).