These days viruses can take advantage of use of common passwords to infiltrate a PC or a PC on your network. Additionally hackers have developed a means of discovering a Windows password that is of 14 characters or less. With this in mind, it's wise to go with a Windows user password of at least 15 characters, with use of both uppercase and lowercase letters, numbers, and punctuation. You can perhaps start with a brief sentence or statement and substitute numbers for letters sometimes. Good typists will have less of a problem with a long password, and depending on the situation you can get by with a shorter, lower strength password (office PC vs. home PC for example). Whether you choose to follow this advice or not, for your Windows user account any password is better than no password.