Earlier this week, Apple held an event for the forthcoming Apple Watch ahead of its 24 April launch date.

At the event, the company promised an all-day battery life of 18 hours, dependent on usage. Its since turned out that those last three words are key, as the Apple Watch product page reveals that the battery could last as little as three hours if used intensely.

Apple states the Watchs total talk time, if used to place a call through the iPhone, is up to three hours. When used to play music or track a workout, meanwhile, it lasts up to 6.5 hours. However, if used purely as a watch – checked purely for the time, five times an hour – the device will last up to 48 hours.

Following the event, Apple released iOS 8.2, an update that makes iPhones compatible with the smartwatch through a dedicated companion app. This is a compulsory part of the update but, given that the Watch is still over a month away, its currently functionally useless except as an ad for the device.

As with the surprise U2 album that was added to users iTunes account last September, this mandatory app hasnt proved popular on social media. Public reaction on Twitter from iPhone users is split between those who think its an effective marketing ploy (such as @Stingray_Travel, who tweets “I see an Apple Watch app on my iPhone. Talk about being tempted”) and those who have had a significantly more negative reaction (like @GradyForrer: “Seriously, Apple seems to have put an app for their stupid watch on my Iphone/any idea how to get it off/amputate at wrist?”).