The slats of the lattice behind Louie are similar and repetitious, but they are not all the same. To keep track of which one I’m working on, I’ve added a black arrow to the reference photo on my monitor.
The wood grain and wear on each slat is different, and the light through the square gaps in the lattice are different. I glance up and down continually as I’m working to check what I’m copying in the reference pic. It can get confusing to get my eye back to the right slat or hole each time I look away. So I move the arrow to the next slat with my cursor as I work my way along. That helps me keep track of where I am, without having to search around with my eye to re-orient myself visually each time.
I glance up and down hundreds (maybe thousands) of times in a day’s work.