I was studying the difference between "except" and "except for" and noticed that in different sources they use them interchangeably in similar examples.
"Everyone was tired except for John."
"Everyone was ready except John."
"Except for Louisa, who away in Berlin this weekend, we'll all be at the party."
"We all went except Tom."
If "except for" is used when what is excluded is different from what is included then why don't they use "for" in sentences #2 and #4?
But in #4 it is required. Perhaps it's according to this definition: "If "except for" is used when what is excluded is different from what is included." As in Louisa is different by not being with the group.
