Sponsorblock is one of the best things I have ever used in the last 5 years.
"You've saved people from 1,927 segments ( 16h 56.3 minutes of their lives )
You've skipped 5,500 segments ( 1d 9h 19.3 minutes )"
Absolutely ridiculous how much filler youtube is filled with to hit the 10 minute marks! I hope they never go down, it's a great free service.
On mobile phones we use vanced, on my nvidia shields we use smarttubenext. Both integrate with sponsorblock automatically.