Apple plans on revealing more details about its long-anticipated Apple Watch at a high-profile event in San Francisco on March 9.

When Apple unveiled the Watch at its most recent iPhone launch in September 2014, it offered precious few details about apps, hardware, and pricing. Although analysts expect the Apple Watch to handily dominate the still-nascent wearable-electronics segment, it’s anyone’s guess as to how well the device will actually sell once it arrives on store-shelves: Some analysts are predicting sales in the tens of millions of units this year, while others believe it will prove a spectacular flop.

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With all that in mind, here are the big things that today’s event needs to answer—and why those answers are important to developers and other tech pros:

Price

We already know the entry-tier Apple Watch Sport will cost $349. But Apple has remained tight-lipped over how much the “regular” Apple Watch and luxury Apple Watch Edition will cost. Over at Daring Fireball, Apple-centric blogger John Gruber—who has a good track record for these kinds of things—thinks the Apple Watch’s pricing will start at $749 and escalate rapidly from there, and that the Apple Watch Edition will cost $9,999 at a minimum.

For developers and app-builders, price could give some clue to adoption rates, which in turn could offer some insight into which apps to build. Given its low cost, for example, the Apple Watch Sport will likely prove the most popular of all the versions, which means a bigger audience for downloading fitness-related apps. But apps tailored to the Apple Watch Edition (whichever those might be) will likely find a smaller audience by default. (But what would go with a $9,999 watch? How about a $999 app?)

Battery Life

Would you buy a watch that you needed to charge (at least) once a day? Considering the rumors about the Apple Watch’s relatively short battery life, that question might soon confront anyone considering whether to purchase the device. If miserable battery capacity proves a drag on Apple Watch sales, it could open the door to rivals—Pebble, for example, is already touting its comparatively lengthy battery life as a big selling point.

App Ecosystem

As with smartphones, this is the make-or-break point. If the Apple Watch comes out of the proverbial gate with tons of useful apps, it could drive up the device’s adoption in short order. But if the device’s app collection remains a wasteland, it won’t just give consumers second thoughts—it might dissuade developers from creating new software for it.