If you're writing Python, the convention is spaces. From PEP 8: Indentation Use 4 spaces per indentation level. (see http://www.python.org/dev/peps/pep

If you're writing Python, the convention is spaces. From PEP 8: Indentation Use 4 spaces per indentation level. (see http://www.python.org/dev/peps/pep-0008/ http://www.python.org/dev/peps/pep-0008/) I'm partial to spaces in general. Most (all?) IDEs can insert spaces when you press the tab key, and doing so will prevent the nastiness that can happen when you mix spaces with tabs.