When you apply for life insurance the application asks how much life insurance you already own to make sure you aren;t over-insured.
Also, insurer's usually limit the amount of life insurance made available for purchase to 10 to 20 times your annual income - again, so you are not over-insured.
Being over-insured may lead someone to consider committing suicide, although most life insurance policies exclude suicide that occurs in the first 2 years (1 year in some states) of being insured.
The best thing to do is use a life insurance needs calculator to figure out how much life insurance you needs, and then request free life insurance quote comparisons to determine how much that amount of life insurance may cost you, and see if it fits your budget.