The Prime Big Deal Days are just a two-day event. Starting on the 10th of October and finishing on the 11th, you get a 48-hour period to find the right deals for you. So be prepared and don't miss out on some great prices on just the thing you need. With so many options you're bound to find just the deal for you.
You may also want to take advantage of and keep an eye out for lighting deals. These are much more limited in stock and time as to what's on offer. There may even be better pricing available for products that make it worth the purchase.