An SEO Myth
SEO Tools are always right
A big mistake is to assume that the tools you are using are always right and accurate. An even bigger mistake is to make snap decisions and change things based on those assumptions.
One of the biggest causes of inaccuracies in SEO Tools is that many tools query a different Google data center to the active one. This means that they could be basing results on a different set of results that are used in another country or worse still on a data center that is being used to roll out an algorithm update. This is why you should always manually check things out before you make any decision based on the results of an SEO Tool.
Another issue is that some tools are old or inaccurate. I have seen a very high profile tool (whose name I will not mention) that offered advice that was just plain wrong. I contacted them and they acknowledge the advice I gave them and quickly changed it. Whilst they were pro active in doing this, it hadn't stopped them charging lots of people for a service that provided inaccurate advice.