Nothing is a waste of time if you use the experience wisely.
Time feels wasted not because of what happens in it, but because we draw nothing from it. The quote shifts the question from "was this worthwhile?" to "what can I take from it?" A dull job, a failed attempt or a long detour can all become raw material, provided we pay attention and put what we notice to use.
That outlook fits what we know of Rodin's life. He was a sculptor who is said to have been turned down by the École des Beaux-Arts and who spent years doing humble decorative work before he became famous. His art grew from patient observation of the human body, which suggests he treated slow, unglamorous work as a kind of schooling. It also echoes the older idea, found in Stoic and practical philosophy, that experience becomes valuable through reflection. As with many popular quotes, the attribution to Rodin is common but hard to trace to a source, so it is best held with some caution.
Suppose someone spends a year in a customer service job they dislike. Rather than writing it off, they might notice how they calm angry people, then use that skill later in management, teaching or negotiation.