This quote is essentially advising against the over-giving or over-receiving of advice, particularly when it is not asked for. The term "niggards" here is used to mean stingy or sparing. The phrase "the worst avarice is that of sense" suggests that the most damaging form of greed is the desire for knowledge or understanding, particularly when it is gained through unsolicited advice. It implies that there is a certain arrogance in assuming one’s own understanding or perspective is superior to another’s.

In today’s world, this quote can be applied in many contexts. In the age of social media and instant communication, everyone seems to have an opinion on everything and is quick to share it, often without being asked. This can be overwhelming and even detrimental, as it can prevent individuals from forming their own opinions or making their own mistakes and learning from them.

In terms of personal development, this quote suggests the importance of self-reliance and independent thought. It encourages us to be cautious of accepting too much advice from others and to value our own ability to make decisions and form opinions. It also reminds us to be humble and considerate in our interactions with others, recognizing that our own perspective or understanding is not inherently superior.