Wasting time is okay. Some people watch sports, play video games, go to the pub, work on that old thing in the garage (and just end up watching youtube videos about other people's projects).
I started taking notes, started cutting down on low-quality infotainment/edutainment (for example while I know folks at SciShow work a lot on their content, put a lot of effort into producing scientifically correct stuff, but it's just not deep enough, it's too fast), and in general try to watch/listen to multiple videos that touch the same topics. (Because many complex things require multiple passes to comprehend anyway, and getting different viewpoints, different presentation helps a lot with that.)
I started taking notes, started cutting down on low-quality infotainment/edutainment (for example while I know folks at SciShow work a lot on their content, put a lot of effort into producing scientifically correct stuff, but it's just not deep enough, it's too fast), and in general try to watch/listen to multiple videos that touch the same topics. (Because many complex things require multiple passes to comprehend anyway, and getting different viewpoints, different presentation helps a lot with that.)