Great question, Dave.
Personally, I'm a HUGE fan of TB's A/B TEST functionality - I used to only do thumbnail tests, and ever since I've started trying out the different title tests, I'm hooked there as well - so, EVERY VIDEO I publish undergoes a bunch of tests to see which one(s) perform better. Once the better thumbnail (I sometimes do 3-4) gets chosen by the audience, I move on to different titles to see which one sticks with the audience (interesting to see that the previously-selected 'winning titles' on one video don't necessarily do well on another - go figure!).
On a side note:
ΓÇ£You never get a second chance to make a first impression.ΓÇ¥ΓÇö Andrew Grant.
Keeping the above in mind, I have a reminder set every 3 months to review a handful of my lowest-performing long-form videos where I check click-through rate, average view duration, audience retention, how many subs I get from a particular video, etc.
IF those stats on the video keep underperforming vs my channel average, I unlist the video. If they're doing okay, AND it turns out that I haven't done my A/B TEST mentioned above on them (as the videos were published before I had TB), I'm doing the above pic/title tests. Once I've improved them, I let them do their thing, and hope not to run into them at the next reminder, which will mean they still couldn't perform despite my best efforts & they'll be removed.
I recon if someone completely new to my channel arrives at a piece of my content, AND gets one of those underperforming videos, s/he might be turned off by it for whatever reason, leave, and unlikely to return. Now, if that video DOES leave an impression (resulting in a like/share/comment/subscribe), that piece of content has done what I like it to do.
BTW - I'm not sure if it was always there, BUT I just recently found out you can do this A/B TESTING with YT Shorts as well... so there, I have started with my TOP performing YT Shorts and doing tests on their titles to see if a different title will see an even better performance. During my 3-month reminder exercise, I've added optimising a number of YT Shorts to that list which might perhaps need a boost via different titles.
My 2 cents.
