Another instance, if you name your daughter as a primary beneficiary and your son as a contingent beneficiary; your daughter will be the only one that receives the death benefit proceeds when you die. Your son will only become the recipient if your daughter predeceases you or cannot be found. However, if you name both of them as primary beneficiaries, they will both receive the proceeds according to the percentage you specified or whoever remains will receive the entire benefit if one passes before the other as is the likely case.
Alternatively, you could name your spouse as the primary beneficiary and your children as the contingent beneficiary. In this case, your spouse will receive all of the proceeds, your kids will only receive the proceeds if your spouse is predeceased. If you wanted both your children and spouse to collect the assets, you can list all of them as primary beneficiaries. In case your spouse dies before you, your kids would still be the primary beneficiaries. If the children are under the age of majority then a trustee must also be elected to look after the funds until the minor children come of age.