You'll find that most of the heuristic evaluation frameworks/criteria/templates are fairly comprehensive in terms of the types of design and usability issues that are summarized.
Of course, having an exhaustive checklist of things to look out for doesn't guarantee that you will necessarily pick up on them all.
So basically you are trying to make sure that:
A. You include the right things to look for when doing the evaluation AND
B. You pick up on the right things when doing the evaluation
And since people have a tendency (or bias) to look for certain things and not others, that is to say, we can be ignorant of particular things for whatever reason, having more than one person helps to address this potential issue.
I think if you can perform the evaluation, it is at least worth the effort of going to a second person, but if you have a good list and a relatively objective point of view then you are still better off doing the evaluation than worrying about what you are going to miss. That will be a caveat for reporting on your activity.