Where there are minor beneficiaries (children or grandchildren) if a Will is silent as to the vesting age of a beneficiary then an executor will have to wait until the child is 21 in order to be able to get a release from the beneficiary.
However, 21 years is a young age for anyone to receive a large inheritance.
How many young people do you know who are able to handle the receipt of a large sum of money at 21?
A large inheritance can be like a lottery win. The young person will find sudden popularity and new 'friends' all keen to share in his or her good fortune.
Consider delaying the age at which minor beneficiaries receive their inheritance. Do it whilst ensuring that there is a power of advancement and maintenance given to the trustees.