I've looked for this, and I'm surprised that no one has requested it, but maybe i just missed it.
I know how to set the number of posts per page, in settings-reading, but what if I want 3 posts on the home page and 10 on any other page, ie categories, tags, authors etc. I'm happy to have the other settings (excerpts, etc) the same. Any thoughts on how to do this? I know it must be in the center loop, but don't know enough PHP to add it.