Watch time refers to the amount of time viewers spend watching your video. The longer viewers stay in your film and the more they are watching your video, the more watch duration you'll receive. If you made a film lasting an hour and you only allowed one person to view the video continuously, without stopping and you were to get 60 minutes of viewing time. If you wish to fulfill the 4000 hours of watchtime need quickly, you can claim that you must create content at least as long as you can and keep viewers on the video. https://youtubemarket.net/en/buy-youtube-watch-time