At a hair under 49, I’ve never been interrupted while donning shoes and socks with anything that couldn’t wait until I was done.
The reason for sock-shoe sock-shoe is that that way you don’t have to keep switching feet – sit down, put your ankle across the opposite knee, put on a sock, put on a shoe, tie shoe if necessary. Put that foot down, then put the other ankle on that knee, repeat.
Aha - now it makes sense. I don’t flip my feet back and forth because I don’t usually put my feet on my knees to put things on them. They stay straight in front of me and I lean over. I usually step into my shoes then lean over and tie them, if needed.
Left first, then right. Sock, sock, shoe, shoe, fasten, fasten (zip, tie, or buckle). The fastening rule is not so strict that it has to be re-done if it happens out of order.
Slightly off-topic, but also sort of on: When going up or down stairs, or even one step, my right foot has to go first. If I should somehow manage to go left foot first I have to stop and correct it mid-way (meaning, get both feet on one step and start with my right foot). Otherwise it just feels completely wrong.
I s’pose I’m another guy at heart. Just to throw something else into the equation…I always put my socks on before I put on my pants while the ball and chain does the opposite. I have often wondered what made me do it this way and I have concluded that it goes back to my teenage years ('bout a million years ago). We wore our pants skin tight and if I remember correctly, we didn’t want to have to bend over to tie our shoes lest the said pants would become…horror…BAGGY! Oh poo. Now you all know how weird I was. (was?)