Once one starts writing more R code the need for consistency increases, as it facilitates managing larger projects and their maintenance. There are several style guides or suggestions for R; for example, Andrew Gelman’s, Hadley Wickham’s, Bioconductor’s and this one. I tend to write closer to Google’s R style guide, which contains some helpful suggestions. I use something similar but:

• I use = for assignment rather than <-, because it is visually less noisy, <- requires an extra keystroke (yes, I am that lazy) and—from a merely esthetics point of view—in many monospaced fonts the lower than and hyphen symbols do not align properly, so <- does not look like an arrow. I know that hardcore R programmers prefer the other symbol but, tough, I prefer the equal sign.
• I indent code using four spaces, just because I am used to do so in Python. I will make an exception and go down to two spaces if there are too many nested clauses.
• I like their identifier naming scheme, although I do not use it consistently. Mea culpa.
• I always use single quotes for text (two fewer keystrokes per text variable).

Of course you’ll find that the examples presented in this site depart from the style guide. I didn’t say that I was consistent, did I?