When you say "good enough" do you mean to rank? To rank #1?
So let's talk about local citations, anyone can go to a forum and buy 300 citations for their business, will it help them rank? That depends:
- is their local business or service competitive?
- is their website optimized for the local keywords?
- does the citation directory source have traffic or authority?
But just firing off 300 citations isn't optimal imo, and enough to rank in competitive niches. What good will it help an insurance agent to have a citation on tripadvisor or urban spoon?
Just like with social media profile links, or forum links
relevance is key. Next consideration for a citation/directory is the
traffic the site gets, if there isn't any not only will it not connect visitors with the business (because there isn't any), but it won't help with ranking either.
Imo you need proper site structure, keyword targeting (on site and off site), citations, and relevant backlinks to both your niche and geolocal service area. To me that's good enough, but then again can't say without the location or niche, it could be incredibly easy or downright impossible...