In some countries, you cannot give your estate away as intended as it is necessary to benefit particular family members, otherwise the courts can amend the Will.

Some legal systems, e.g. Code Napoleon, Civil, Islamic, and some Common Law jurisdictions, restrict a person's freedom in disposal of assets. Certain relations or relationships evolved from blood, marriage, or even cohabitation can have an irrepressible right to share an other's estate.

In many instances, an appropriate offshore structure can avoid Forced Heirship.

See "Don't Just Die Anywhere!" for a humorous view, yet packed with information, concerning Forced Heirship.