A writer can either choose to use bullets or else stick to conventional (or in certain cases non-conventional) numbering. Are there set guidelines about when to use what? Is the use of numbering preferred over bullets in more professional settings (example, academic writing, technical reports, theses, etc.) or is it left to the choice of the writer?
In everyday writing, (say on the web, or an email) I'd use bullets where possible. I think they're more accessible and quicker to scan. Unless there were some reason to actually number things. The Wikipedia style manual spells this out well:
In academic or tech writing, the governing style sheets or style guides (MLA, APA, etc.) should always be consulted. I'll leave it to our resident tech writers to provide more detail, but I'd consult those resources and only then use the logic above: Use my own preference for bullet points unless there's a reason not to.
It's worth noting that style guides all have specific requirements for how lists are used and formatted. APA at least seems to boil down to similar but more detailed advice as the wikipedia style guide; i.e., have a good reason for using the format you employ.