For strings where it matters whether I use single or double quotes, I use single or double quotes were appropriately. For strings were it doesn't matter - strings that don't contain quotes, backslashes or dollar/at signs, I tend to use double quotes. I do that because it lowers my expected number of keystrokes I need when I'm going to change the string. I'm far more likely to add a newline or an interpolated variable to a string than to add a backslash, or a dollar sign that I don't want to be interpolated. If my quotes are already double quotes, I just add my newline or variable, and be done. Else, I have to add the newline or variable, go the beginning of the string, change the single quote to a double one, and do it at the end of the string as well. In a typical program I write, for the majority of the strings it doesn't matter whether I use single or double quotes - but for the strings were it doesn't, those needing double quotes outnumber those that don't by a long shot. To top that off, I can always escape a dollar/at sign inside double quotes by inserting a single character - single quotes don't have an easy way of indicating a dollar/at sign should interpolate.