These days anybody who owns a website is going to be besieged by aggressive SEO sales pitches. You'll be told that your SEO pretty much sucks, and it's damaging your business. Let's get a few things straight. SEO is an advertising tool which exists alongside and complements all your other marketing channels. Your investment in SEO needs to be apportioned relative to all your customer engagement strategies. The level of investment also should be apportioned relative to measurable traffic goals which you set.
Those goals in turn have to be set relative to other related goals in the arenas of revenue and profits. In other words, investing in SEO needs to be contemplated relative to the entirety of the puzzle. Salespeople shoving this one piece in your face and telling you that you need it are just blowing smoke.
Making SEO decisions rationally is a challenge for many companies because SEO often resides in the domain of IT and is hidden in the budget of IT. Things get done just because they're possible, wasting time and money.
Towering clouds of disinformation surround two key topics: "organic" SEO and "local" SEO. "Oganic SEO" refers to all the stuff you can do right on your own website to make it work better and rank higher in Google. In many cases it will be enough.
How much you need to spend on it is relative to what your competitors are doing. In your home market, you'd be surprised by how few local companies place a big bet on organic SEO. First, hire somebody to find out what they're up to. SEO sales pitches are totally worthless unless based on solid intelligence.
"Local SEO" refers to off-page factors such as inbound links to your website from referring domains, your presence in online directories and reviews in local business directories. Google has been assigning increased weight to these variables. They can make a big difference. Again though, dive into local SEO in relation to how deeply your competitors are invested; and in relation to the effectiveness of your other marketing efforts.
You also may hear mention of the third leg of the SEO stool - an ineffable variable called "quality." That one little word contains a long list of ingredients, but exactly what they are and how they are weighted is known only to Google. Google uses a secret algorithm to grade the relative "quality" of competing websites.
Smart people have dedicated themselves to reverse engineering the quality algorithm for the purpose of website tweaking. They may well be able to help you out. Still you need to ask how necessary such an investment would be, relative to your current position in the marketplace.
I recently did a consult for a customer considering evolving to a whole new site. They've done very little SEO and still come up number one because they are in a very small niche with only a few players. None of whom are playing the game. We decided to move those SEO dollars elsewhere.
It turns out that Einsteinian cosmology also has some things to teach us about modern Internet marketing. What you really need is all relative.