I love learning English through YouTube lessons, but when the internet goes down on the subway, the lesson stops at the most interesting part — it's awful. I tried a bunch of converters until I found YouTube downloader service https://getmp3.one — just copy the link, click mp3, and in 5 seconds the lesson is in your pocket, without ads or registration. Now, before a trip, I download 2-3 videos on grammar or conversation — I listen to them offline, and my progress has improved. If you also learn on the go, this is a real life hack. Try it, you won't regret it!