To an outsider, they appeared done. The goal was to produce monotypes of people wading in water, and here they were: black, white, and lonely, as intended.

But to Clara Lieu, the artist who made them, they were incomplete. “This is a strange thing to say, but I felt like I didn’t think about them enough,” she says. “I want my pieces to go through a cycle of thought and consideration, and with this, it was almost like the work got made faster than I was ready for it to get made.” Her feelings speak to an age-old dilemma artists and creatives face: the ability to determine when a piece of work is truly done.

Sometimes, the decision is driven by external factors: a deadline, the evaporation of funds, the death of the artist. Artist Alice Neel decided her 1965 portrait of a soldier headed to Vietnam was finished when the subject didn’t come back for a second sitting.

But in the absence of external circumstance, the decision to put down the brush (or pen or chisel) has everything to do with the mind-set of the artist. When Rembrandt was asked why so many of his works look unfinished, he famously replied, "A work of art is complete when in it the artist has realized his intention."

It comes down to a feeling: Either it’s done or it’s not. Lieu, who teaches as an adjunct professor at the Rhode Island School of Design, says it’s a sense that develops as you mature as an artist. She often advises her students to overwork at least one piece, just so they can better develop their personal litmus test. “I tell them, ‘You have to do one drawing that you just murder – that you just destroy and totally overwork.’ Once you’ve gone too far, it becomes easier to say to yourself, ‘Okay, that was overboard.’”

For many creatives, knowing when a piece is done is almost never dictated by a feeling of overwhelming joy or gratification. New York City–based animator Yuri Fain says it feels more like the completion of a household chore. “I never step back and go, ‘Yuri, oh my gosh; that’s amazing!’ Until it’s done, I’m annoyed. And when it’s done, I’m, like, slightly less annoyed,” he says with a laugh.

Sometimes, the decision that a piece is finished comes from a fear of ruining it. Other times, the decision to end a work comes from just being sick of it. Artists and creatives often speak about how they start off being excited about a project and then lose interest or start to hate the idea along the way. “I’ve done so many things where I’m into the idea and it’s going to be so cool. Then the minutes and hours go by, and I feel more frustrated with it than when I started,” says Fain.

While emotion is a huge part of the process, there are also practical steps an artist can take in determining whether or not a piece is finished. Artist Nicholas Wilton, who runs creativity workshops and online courses through his company Art2Life, will sometimes snap a picture of a painting and save it on his computer to see what it looks like in thumbnail form. Doing this helps him get a bird’s-eye view of the piece, which helps him decide whether it’s complete. “There’s the close-up view and the 30,000-foot view. To make something really strong, I believe both of those views have to be satisfying and really powerful,” he says.

Other strategies are more obvious. Many artists find value in committing to a deadline, the way they would for any paid work. Many also find value in putting the work away for a period of time. Whether it’s two days, two weeks, or two months, an artist is bound to come back to it with fresh eyes. There’s no right or wrong answer; visual artist and designer Mike Perry has one of the most fluid views of his work, sometimes adding new details or entirely painting over pieces he first painted years ago.

External feedback may also be valuable. After Lieu created her unsatisfying monotypes of people wading in water, her husband happened to see the plexiglass plates she had used to print them and mentioned he liked them more than he liked the art itself. “As an artist, you don’t want to hear that the plates look better than the finished product,” she laughs. “But then I thought about it and realized he was onto something.” The plates, which had been sanded down and thus had a frosted, translucent quality, inspired Lieu to sand sheets of plastic and draw on them. Those became her finished product.

Of course, outside feedback has its limits. As an artist, the risk you take by giving others too much power over your work is that you end up with something that doesn’t feel like it’s your own. Wilton says it’s ultimately about fulfilling your own vision. “I’m a human being and I like people to favor my work, but it is not at all the driving force. The driving force is what is a ‘yes’ for you.”

There’s beauty in the mystery of that choice. Two years ago, the Met Breuer museum in New York City hosted an exhibition called “Unfinished: Thoughts Left Visible.” It contained nearly 200 artworks spanning 600 years, all of which were left incomplete for a variety of reasons. One of the gems was Jan van Eyck’s “Saint Barbara,” a 1437 metalpoint drawing that appears to have been intended as an altarpiece painting. The sketch is intricate, but the painting itself is half complete. In its review of the exhibition, The New York Times highlighted the piece, asking, “Is that what it was meant to be, an ultravirtuosic preparatory drawing waiting for paint to be added? Or was it conceived to be from the start what it is now — self-sufficient, done?”

Van Eyck signed and dated the piece. And maybe that’s enough.