I’m glad I am not the only one to worry about such things. Back when I first started the Harvey Mercheum website, a double greater than symbol was the title separator. I do not recall if I chose that, or if it was a default, either in WordPress itself, or in the Suffusion theme I used originally. I think it was when I was setting up Yoast that I changed it to the vertical bar, also known as the pipe. According to this article from Search Engine Journal, I made a good choice:
Three Ways a Pipe or Dash in Title Tag Makes a Difference
