I like to make mine now so it's ready for holiday baking. I make a double-strength vanilla, saving one bean out for vanilla sugar.
I order Madagascar beans from Penzey's online (they come in threes).
I use a 375ml bottle of vodka and add 5 split beans to it.
The sixth bean I split almost to the top and insert in a jar of sugar for vanilla sugar. Vanilla sugar is excellent for donut sugar, sprinkled on sugar cookies or added to custards or coffee. It's excellent in plain scones for a subtle hint of vanilla. Be sure to leave the bean peeking at the top of the sugar so you can pull it out and stir up the sugar occasionally. Over time it can lump from the bean moisture.