Do You Capitalize Joe in "Regular Joe"?

As a general rule when you use a name as a substitute for a person in general do you capitalize it?

For instance the name Joe when used in

“He’s not fancy he’s a regular Joe.” Or would it be “…he’s a regular joe” ?

Or “He met up with some Sheila, at the fair”

Interesting… I first thought “Why wouldn’t you capitalize Joe. It’s a proper name.” and I always see it in print as such in the “regular Joe” sense.

But then it seems that prostitutes’ customers are referred to as johns, with a lower-case J, as is the bathroom.

Yes, I would. ISTM that’s how I’ve always seen it.

And then a cup of coffee can be referred to as a cup of joe, further muddying up “the rules”. :dubious:

I would say “regular Joe” but “some sheila”.

dictionary.com kind of backs this up, mentioning only the lowercase sheila and saying [regular] Joe is “sometimes lowercase”.

John le Carré refers to some espionage agents as “Joes” and, in this context anyway, he should know.

Alas, he doesn’t know.

He uses “Joes” in A Perfect Spy (1986) and “joes” in The Secret Pilgrim (1991). For all I know he might mix things up a bit in these and other books but forgive my lack of thoroughness in not following this up.