You have a retirement account with designated beneficiaries in case you die. Great!
You have life insurance in the event that you die. Great
Now what if they conflict and one says one thing and the other another? Well if you the designated beneficiaries conflict with wants in the will and with wants in the insurance and retirement accounts, then (drum roll please)...the designated beneficiaries will end up getting the individual assets instead of what it says in your will.
If you have really old retirement and insurance accounts this could cause some serious problems. Have you been divorced and not changed them? Have you had a falling out with a relative? Did one of the beneficiaries die?
You need to go through each asset and make sure that it is consistent with whats in your will. If you don't you could leave a lot of heart-ache and fighting for your family in the unfortunate event of your death.