Ecclesiastes chapter 12 can be interpreted in at least 2 different ways.

I've always been familiar with the interpretation found in the SDA Bible Commentary. The companion book to the quarterly by Doukhan gives an entirely different view. I found it very interesting:

SDA Bible Commentary: "The highly figurative imagery of vs. 2-6 has been variously interpreted. Many commentators, both Jewish and Christian, have explained this sequence as a description of the depleted physical powers of the sunset years of life, and the separate figures as referring to anatomical details of the body."

the difficulty with this interpretation is how to relate the various symbols of chapter 12 to body parts or an aging person's experience, as the sun, moon, stars, the door, grasshoppers, etc; interpretation is highly imaginative and indefinite;

Commentary on Ecclesiastes by Jacques B. Doukhan "In chapter 12 the orientation shifts from an individual to a cosmic perspective... After an illusion to old age, Ecclesiastes moves on to something more terrible than old age: The sun and the light / and the moon and the stars grow dark. The text is not about old age (as commonly
interpreted) but about the time of the end." pp 119, 120,

interpretation of the various symbols of chapter 12 can be found in Scripture, pointing to events at the time of the end: sun, moon and stars losing their light; the difficult days at the end of time; the blossoming almond tree as a sign of God being ready to perform His word (Jeremiah 1:11, 12); two women grinding at the mill, one taken & one left; humanity (adam) going to their grave; the breaking of the menorah lamp at the funeral; the death of humanity on this earth at the Second Coming;

v. 9-11 claim divine inspiration for Ecclesiastes: the words of wisdom were given by one Shepherd; guided by the Holy Spirit, Solomon compiled pieces of wisdom from his own Israelite tradition and from Near Eastern literature; he "set these in order" and made them beautiful; "he was creative", "an ingenious artist", "an original thinker", "he worked hard and skillfully to produce his masterpiece".

v. 12, NIV, he cautions against adding anything to these words, reminiscent of a similar caution at the end of Revelation;