I'm two months into my annual - and I'm the one doing it.
I never understood how aviation mechanics took so long to do the seemingly simplest thing. Then I built my own plane and I finally understood.
Everything is painstaking, everything is so oem-specific, nothing is accessible and on and on. I've spent 45 minutes getting a tiny nut on the end of a screw. The easiest tasks takes hours. Just walking around the wings of an aircraft ends up putting miles on your legs and wasted time on the clock. And the ONE screw you lose is the ONE screw you don't have in your parts supply. And that one screw is going to take two weeks to get.
And then you realize you also lost the washer! Another two weeks wait for a washer.....
Now I realize most A&P's are incredibly fast and efficient at their jobs.