I recall 30-35 years ago when I was a teen and my dad worked in the concrete construction business. He was a foreman and would travel from job to job to check in on his guys and the progress of their work. I worked a couple of summers and got to ride around with him.

The crews loved him. Beyond his care for them as people, he was super organized in his work. He knew details, remembered conversations, and made things happen. These were also the days before smartphones and task management apps. 

So what did he use? I distinctly remember.