Rhetoric is a powerful tool. Last year I wrote about "staying beneath the parapet." That's the technique of not giving away what you think, of saying as little as possible. Another rhetorical trick is appealing to experts (argumentum ad verecundiam) or experience (a version of ad ignorantiam). And like every rhetorical technique it has both strengths and weaknesses and can be used for both good and evil.
Generally, the way it works is to have a reputable source, 'an expert' supporting your argument. For example, you see this in parenting forums or debates about Climate Change or Islam. The weakness with an appeal to experts is that your opponent may have more or better experts to appeal to and so it becomes an escalating arms race of who has the best expert. An appeal to 'experience' works in a similar way. You either point to a friend's experience that supports your argument or just as powerfully subtly highlight your opponent's lack of experience. The classic example of this is during a debate about abortion, where male voices are often excluded because they lack the experience of "being a woman." The argument can be defused, ironically, with an appeal to a favourable expert who has the alleged experience but ultimately questioning the right for anyone to make judgments and observing the consistency of logic is more powerful.
Sometimes it's important to provide experts that support your view. This is because good ideas have a long provenance, you want people to know that your idea has a reliable pedigree. An appeal to experience can also be helpful when someone is unnecessarily assertive or in genuine need of assistance. But it's also important to be self-aware that you're using those tools and rely on the truthfulness and goodness of the ideas themselves to ultimately win over your opponents.
[Picture from unsplash.com of a random lab, where no doubt, experts are at work, but I can't say with certainty.]