It is as important as just about anything in your home. Not just one document as it is completed; but, to continually keep it updated as well. Documents would include those items you would shred to those documents that are considered as final documents. Living wills & final will and testament are two. These two are likely the two documents that are complete in most households. They are also documents that more often come under scrutiny by persons whether it be family or others. The point would be, when you do process a document, final or immediate, pay attention to detail and be aware that it is subject to change.
You are not exempt if you do get a document processed at an attorney's office. Remember, your document is only correct and legal based on what you state in filling it in. Which brings me to what some may have said about getting a document online. So, all depends on what answers you fill in the blanks with, how truthful you are, how you keep it up to date, how you store it for others to find, and that it is readable.
Being able to process your online legal document on your home desktop computer may be the biggest hurdle to cross. In obtaining your online documents and being complimentary of them, you would have to
a. choose the correct online document
b. be comfortable in typing it up
c. download it properly to your desktop computer
d. be able to print it ...and...
e. store it properly and be able to retrieve it