For most people making a will is a sensible decision. The thing to remember is that in the UK people are free to leave their estate to whomsoever they wish by will. That is not the case in many other countries. So, if you do wish to benefit a charity, for instance, or a partner to whom you are not married then you must do so by will. It will not happen otherwise.
Wills can also have an extremely important role in minimising the impact of inheritance tax.
Solicitors usually charge quite modest amounts to draft a will - it is often something of a loss leader which it is hoped will attract the rather more lucrative probate work. It is unlikely to be a great deal. Cost is rarely a good reason to be without a will. It will be seen that this is a much narrower category than people usually imagine. Of course, it is not very often that parents exclude their children from benefitting under their wills but, sadly, sometimes it is justifiable and one should not be put off making such a decision because of a mistaken belief that adult children could contest a will.