When preparing your own will, it is easy to overlook some legal formalities that could cost you (or others) much more than you think. One of these is having proper witnesses for your will.
It is a requirement to have two witnesses to witness your signature on a will. If this requirement is not met, it would require a court application to determine if the will is valid. If the will is not valid, then a previous will or intestacy laws would determine who inherits.
There are also restrictions as to who can be a witness on a will. If you are a beneficiary under the will and you are also a witness on the will, the gift that was left to you as beneficiary is no longer valid. This offers protection for will drafter in case the beneficiary is forcing you to sign the will. While it might not be your intention, you could prevent someone from inheriting their gift, or they could have to take legal action to inherit under the will (costing them money).
Under a holograph (handwritten) will having witnesses is not a requirement. This type of will can come with its own set of problems though in relation to witnesses. A handwritten will must be entirely written in your own cursive handwriting (not typed, printed or handwritten by another person). Your handwriting must then be properly identified by someone, which could require previous writing samples or could even involve hiring a handwriting expert to identify your handwriting. All of this would be submitted under a court application to validate the will, costing more money.
All this said, using a lawyer to draft your will provides you with an expert who can avoid these legal pitfalls and help save you money in the end.