Your last will and testament won't go into effect until after your death, so it's best to assure its validity before you sign it. The requirements for wills vary between states. Some jurisdictions require witnesses, while others mandate the presence of a notary public. In California, you can opt for a witnessed will, use a statutory will, hire a lawyer or write out your own will longhand. Each method is valid if you follow the statutory rules.
If you are old enough to vote in California, you are of age to make a will. Anyone 18 years or older can sign a document setting out who will inherit her property. Under California Probate Code 6110, a written will is valid if the maker signs the document or affirms her signature in the presence of two witnesses, who also sign the will. Witnesses should be disinterested. If one of the witnesses stands to inherit under the will, the law presumes that he used undue influence and the burden is on the witness to prove otherwise.
You don't always need witnesses to create a valid will in California -- you may write out your own will in longhand and sign it. This kind of will, called a holographic will, is expressly permitted under section 6111 of the Probate Code. No special words are required. If the material provisions of the will and the signature are in your handwriting, the will need not be witnessed. The court's primary concern in evaluating a holographic will is whether it represents the intention of the maker.
California offers its residents another option -- the statutory will, found in section 6240 of the Probate Code. Anyone can use the statutory will by obtaining a copy, filling in the blanks to identify who is to inherit property, and signing at the bottom of the will. Two witnesses must also sign. Any additions or deletions to the form language -- other than filling in the blanks -- may invalidate the will.
Some people hire attorneys to prepare wills. Attorney-prepared wills are subject to the same witness requirements as statutory wills. The Probate Code specifies that the statutory will is not designed to reduce death taxes or other taxes. It recommends that you talk to an attorney to do tax planning in the following cases: "(i) your assets will be worth more than $600,000 or the current amount excluded from estate tax under federal law at your death, (ii) you own business-related assets, (iii) you want to create a trust fund for your children's education or other purposes, (iv) you own assets in some other state, (v) you want to disinherit your spouse, domestic partner, or descendants, or (vi) you have valuable interests in pension or profit-sharing plans."