The “Super Bowl of Shopping” is upon us once again. This year, the bacchanal better known as Black Friday will be especially crucial for retailers given the pre-election angst that stores say cost them billions in sales. The long shopping weekend gives them a chance to make up for that lost income. By some estimates, the weekend generates 15% of November-December sales, so there’s no denying its importance.

Industry analysts are almost unanimous that the 2016 holiday shopping season will be better than last year’s, what with higher wages, lower unemployment and a boost from gas prices. The National Retail Federation (NRF) is expecting sales to be up 3.6% in what would be one of the industry’s best Christmas periods in recent years. And this weekend will be a good gauge of whether stores are likely to hit that target.

(The weekend could also be a good gauge of the health of the overall economy. For more, see this Fortune story.)

Of course, it’s good to remember that the weekend, for all this hype it gets, doesn’t guarantee Happy Holidays for stores. In 2014, NRF reported that sales fell 11% for the weekend. But the season as a whole turned out to be strong because stores were simply rolling out deals sooner in the season, pulling sales earlier in November.

Some chains have a lot more riding on a successful weekend this year. Target (TGT), Kohl’s (KSS), Macy’s (M) and J.C. Penney (JCP) are particular eager to get back to sales growth, while Best Buy (BBY) wants to show its recent comeback can last. It won’t be easy: Walmart (WMT) and Amazon.com (AMZN) are being super-aggressive on price.

Here is a look at what shoppers and retailers alike can expect this long shopping weekend:

1- More shoppers will hit stores and the web than last year

Starting on Thursday, some 137.4 million Americans are expected to either shop online or hit stores over the four days, according to a survey released last week by NRF and Prosper Insights & Analytics. That would be up from 135.8 million last year.

2- More shoppers will go online than to stores

In 2015, for the first time, roughly the same number of shoppers went online as visited stores. Indeed, Slice Intelligence estimates that Black Friday e-commerce sales rose 40% last year compared to 2014. And a Deloitte survey found that shoppers expect to spend 51% of their holiday budget online this year.

To combat Amazon.com, chains like Walmart, Target, and J.C. Penney now start their online deals at the stroke of midnight on Thanksgiving morning so they can compete until their in-store sales start. Still, don’t write off brick-and-mortar stores: the International Council of Shopping Centers’ 2016 Black Friday Consumer Survey found that 81% of this weekend’s shoppers would hit stores.

3- Aggressive fighting online (but Amazon will win)

Forrester Research has forecast online holiday season sales will rise 13% and top $100 billion for the first time this year, and retailers want in. Walmart, emboldened by its recent successes and massive investments in its mobile app and integration of stores with e-commerce, is going all in. The retailer has tripled its online assortment to 23 million items, thanks largely to an overhaul to its marketplace completed this year. But it is also starting its aggressive Cyber Monday sales when the dust hasn’t even settled on Black Friday.

A Kantar Retail survey recently found that 50% of people plan to shop during the holidays at Amazon.com, up 5 percentage points from last year. And BloomReach says 50% of all e-commerce searches start on Amazon, which shows that it’s getting harder and harder to fight Amazon and it’s super-sticky shopping app. Still, the brick and mortar retailers are using their #1 resource–their stores–to ship more quickly and to give shoppers the option to pick up an online order in stores. And Walmart and Kohl’s have introduced shopping apps this year to speed up service and keep customers from straying to other sites.

4- Thanksgiving emerges as a peer to Black Friday

The news that certain chains, like Target, Macy’s, Penney and Kohl’s are opening their doors on Turkey Day always meets with jeers in some circles. But the fact remains, they wouldn’t do that if people didn’t show up. ComScore estimates that online sales could exceed $1 billion on Thanksgiving for the first time. Last year, Thanksgiving Day was the #2 in-store shopping day of the year, according to NPD Group, and rising quickly. In 2015, some 26% of shoppers hit stores on Thanksgiving, compared to 44% on Black Friday. But remember, most stores are closed for most of that day. (J.C. Penney gets the earliest start, opening its doors at 3 p.m.)

It looks like, for most people, Thanksgiving is still a day for tire kicking and browsing for ideas more than for actual spending, what with 29 days left til Christmas. RetailNext doesn’t rank Thanksgiving in its top 10 biggest spending days for the year. Most of those are in the two-week run up to Christmas as shoppers start to realize that, hey, the big day is almost here.

On the bright side, stores in general won’t be open any earlier on Thanksgiving this year, with the one exception of Macy’s opening at 5 p.m. rather than 6 p.m.

5- More Black Friday discounts on toys and TVs, fewer on clothes

Walmart is going aggressive this weekend. According to Wall Street firm Jefferies, the retailer’s discounts are 4 percentage points deeper this year, widening its price edge over Target. Walmart is focusing those discounts on categories that are key to getting shoppers in stores on Black Friday: Jefferies estimates Walmart’s deals on TVs are about 11% deeper this year. But Target is also ramping up its deals this year, with much more messaging about discounts than in Black Fridays past.

But you may be disappointed if you want to buy clothing on the cheap. Kohl’s, Macy’s and Penney have all been careful about keep inventory lean to reduce clearance sales. Jefferies’ analysis of Black Friday ads found apparel discounting was down at most retailers this year, including 6% less discounting at Penney.