Preparing your own Will is not really advisable. A Will must conform to strict legal requirements otherwise the Courts may decide it is not valid. If this is the case your assets will be distributed according to a predetermined formula and not as you intended. Anyone who is not legally qualified risks making a mistake, creating uncertainty or losing opportunities for good estate planning if they make a Will for themselves.
The precise wording of a Will is a specialised and important legal task. The ordinary meaning of words is not necessarily the same as their legal meaning. Ambiguous wording is extremely common in home-made Wills and may result in substantial cost and delay in having the Supreme Court resolve the ambiguity.
A Will is an important legal document. It is therefore advisable to have your Will professionally drafted and ensure your wishes are properly recorded and carried out.