Making a Will is a wise and important thing to do. You will have peace of mind knowing that your estate (that is, everything you own) will pass to your chosen beneficiaries.
Without a Will, your estate could pass to relatives you have not seen for years.
However, some people chose not to include a member of family in their Will. This may be a child or sibling and could be for a number of reasons, for example, a falling out or estrangement and even though most people would like to think that the relative would not try to contest the Will, there is always a risk that the relative could claim under the Inheritance (Provision for Family and Dependants) Act 1975 and if this happens then dealing with your estate can be lengthy, complex and expensive.
If you have a reason for leaving a relative out of your Will then we strongly recommend that you leave a personal letter with your Will explaining the reason why you have not included this particular person (or persons). You will not be around to explain why and a personal letter would help against any potential claim.