When is `\[` preferred over equation* environment?

Question

When is it preferable to use \[ instead of equation*? I find I often use the equation* environment in the following way:

\begin{equation*}
some expression
\end{equation*}

Should I instead be using the \[ as below?

\[
some expression
\]

Answer 1

The final lines in amsmath.sty are

2665 \DeclareRobustCommand{\[}{\begin{equation*}}
2666 \DeclareRobustCommand{\]}{\end{equation*}}
2667 \endinput
2668 %%
2669 %% End of file `amsmath.sty'.

This means that, when you load amsmath, \[...\] is completely equivalent to \begin{equation*}...\end{equation*}.

The latter is better if you use numbered equations, because it's easier to switch from unnumbered to numbered or conversely by removing or adding *.