Ask a room of engineers what "significant" is, and you'll likely get a room full of engineers' worth of answers.

My definition of "significant" is whether or not its inclusion results in a change that would render the design from acceptable to unacceptable or from unacceptable to acceptable.

If you've been running the analysis and finding that it holds no impact in light of rules of thumb you could instead be using with an acceptable degree of precision, then perhaps.