From my research. Take that for what it is worth.
Spend 90% of your time working on your intro... why?
Look at the average watch time of your videos. If your videos average 10 minutes, it is probably going to be like 3:30-4:00. Meaning the majority of the people are not even going to see your extro. Mine are almost always just a simple 20 second clip, where I have room to pu tthe subscribe button and what to watch next. Took me a whopping 2 minutes to do. My intro was a bit more complicated.
Also like
@Armchair Economics Guy mentioned, if someone gets on to your vids and starts to binge, it could get annoying real quick seeing the same thing back to back.
I usually break this up. I have a 20-25 second quick intro / teaser for the EP. Then the intro and roll into the meat of the video.
I am in no way trying to grab views, but here is a good example of how I do it, if you are interested.