Creators on YouTube get to decide how many ads appear and when they appear on each video they create (as long as they're in the partner program, which is open t

Creators on YouTube get to decide how many ads appear and when they appear on each video they create (as long as they're in the partner program, which is open to basically anyone with >1000 subscribers). If the videos you're watching have a lot of ads at inconvenient times it's because the creators wanted them there.