Do you call yourself an "adviser" or an "advisor"? Chances are, if you're a Registered Investment Adviser, you call yourself an "adviser." On the other hand, if you're a broker, you probably refer to yourself as an "advisor."
At least that appears to be the standard. Surprisingly, though, many practitioners use both terms interchangeably.
According to Grammarist.com, "adviser and advisor are both accepted spellings of the noun meaning one who advises or counsels. There is no difference between them. But adviser, the older version, is listed as the primary spelling in most dictionaries, and it is about five times as common as advisor in current news publications from throughout the English-speaking world."
For those more old school, the Oxford Dictionary says: "The spellings adviser and advisor are both correct. Adviser is more common, but advisor is also widely used, especially in North America. Adviser may be seen as less formal, while advisor often suggests an official position."
When it comes to legal definitions, however, a vowel can mean a lot. The official U.S. Government document that defines and regulates the provision of investment advice is titled the "Investment Advisers Act of 1940."
Notice the spelling of the term.
Not all aspects of financial planning and financial advice require providing investment advice. For instance, such staid examples as budgeting, debt management and insurance coverage generally fall outside the realm of investments. Certainly these professionals are not providing investment advice. Why invite potential compliance headaches by calling these people "advisers?"