Videos trending on YouTube are getting longer. Whereas many videos used to run seven or eight minutes, the most recent popular videos are as long as 60 minutes. Felix “PewDiePie” Kjellberg’s recent video is 30 minutes, for example, and Shane Dawson’s latest documentary is 60+ minutes. The driving force behind the trend is creators’ efforts to make more money via advertising. Ads run at the beginning of videos that are less than 10 minutes long, while YouTube allows the insertion of ads in the middle of videos that run longer than that.

The Verge reports that YouTube creator Shelby Church “found that she made three times as much revenue for videos that ran over 10 minutes than those that were shorter … incentivizing creators to make longer videos and plug more ads.” Based on under 10-minute videos, Church made $1,800 in January; by adding two ads in the middle of a 13-14 minute video, she made over $6,000 in June.

Now, “makeup channels started producing 30-to-40 minute tutorials, explainer videos became 30 minutes long, and even apology videos started to run long.”

YouTube boosts the longer videos because its algorithm “prefers content that keeps people engaged, encouraging them to spend even more time on the site.” A report by Pew Research Center stated that “the average length of a video among the top 250,000 channels was between 13 and 14 minutes,” but the 30-minute video is trending, in “longer video essays, more extravagant vlogs, makeup tutorials, and commentary … alongside political content, lengthy explainers, and documentary series.”

YouTuber Lindsay Ellis, whose videos can be 45-minutes long noted, “it’s easier for people to stay on YouTube if you’re watching just one thing as opposed to 200 cat videos.”

But not all videos work well in a longer format, “which can lead to worse videos.” “I do think that doing longer videos for the sake of having longer videos is bad,” said YouTuber Natalie Wynn, known as ContraPoints, whose videos are usually 30+ minutes. “A video should never be longer than it has to be.”

In fact, some prominent YouTube creators are criticized for “unnecessarily lengthy videos,” and Wynn stated that the longer-video trend will eventually peter out. “At some point, someone with a very punk rock attitude is going to come in and change everything,” she said. “People will have gotten sick of long videos. Someone’s going to go really concise, and publish videos that are going to be way better than all of ours somehow and much shorter. Then that’s going to be the new step.”