Many SPOTS become BLIND due to the driver's haste.
Sure you may have turned your head and eye-balled each mirror, but
..if you do that too fast you'll miss something anyway !
ssslllloooowwww down and you'll see everything.
Even with convex blind-spot mirrors, you'll miss the fact that something is there unless you take the extra second too assess what you're seeing there.
When training for my pilot's license they taught a method of searching the sky for others.
-- You can notice something moving....if you're not. --
ie; hold your gaze still for a bit , then you'll catch movement, even in your peripherals, that escape you if your eyes are moving too.
This works well with automotive mirrors as well. I back all three truck into my driveway so as I pull to the curb to prepare to swing out for backing in, I look into the yard area for two grandsons bolting about.
then swing the truck around and check the mirrors. Then ease back in reverse.
Keeping vision stationary for a second often reveals the movement I'm looking for.