If you're considering a blog for your firm, the first step is simply to understand why you would use the blog in the first place, as that can impact everything from the content you produce, to how often you produce it, to who you send it out to.
For instance, if your goal is to use your blog as a tool to help generate new business, it needs to have regular new content that is relevant to your audience—updating once a month is a bare minimum, but twice a month or even once a week is preferable (and the more frequent blog posts can then be consolidated into a monthly newsletter). The content should have actionable tips and guidance—material that people who aren't otherwise very familiar or engaged with your firm would be interested in reading and might share with others (especially in today's age of social media).
The content should be targeted at issues relevant to your clients' lives; if you're not sure what kind of content is relevant, that may be a sign that you need to take a step back and do a better job defining your target market in the first place. And perhaps most important, you should have a way on your website, and as a part of your general marketing process, to add people to the mailing list for your blog updates, so that you can occasionally push the content out to them, turning a one-time visitor to your website into an ongoing drip marketing prospect who may eventually become a client.
On the other hand, if your goal is to use the blog to communicate relevant news and updates on the firm to your existing clients, the content may be more irregular, as it's really only necessary when there's something to actually communicate. The content may or may not be actionable; it might simply be informative. It's likely not information you would communicate to prospects at all (at least, not all of it), but you should have a process to regularly distribute it out to your existing clients from time to time (e.g., once a month) so they're aware of both the content itself, and that your blog is the place to go for updates.
In terms of SEO, the reality is that any of the above types of blogs will certainly help your rankings in search engines like Google. However, if the sole goal is to add some occasional fresh content to your website to help it rank higher on search engines, you might even consider using some pre-written articles that are not specifically about your firm or written exclusively for your target market, as long as they are generally relevant to your prospects and clients, such as the content from Forefield Advisors or Bob Veres' Client Articles. In other words, the more you want to use your content for proactive marketing outreach, the more it should be written in your words for your target market; the more it's just about getting some better SEO, the more you can incorporate some outside content.
The bottom line is that if you're going to invest time, effort and perhaps a little money into a blog, you should know why you're doing it, so that you can craft the blog accordingly, from the content you create to the people you distribute it to. Alternatively, if the reality is that you're not concerned about SEO (e.g., your site is already easy to find in search engines), you have other means to communicate to your existing clients, and you don't want to use a blog as part of a drip marketing approach, you may not need to have one at all. Although at some point down the road this may become a standard practice for most firms, the reality is that right now, inbound marketing for financial planning firms is still in its nascent stages.
So what do you think? Do you use a blog as a part of your firm's marketing to prospects? Do you use it as a communication tool for existing clients? Is search engine optimization a concern for you (or has it become one now that you've read this!?)? Are you considering establishing a blog for the future?
More in-depth analysis by Kitces of the reasons to consider a financial blog for your firm can be found in Part 1 on AdvisorOne.