Apple has revealed how long you should go before replacing its products.

The US tech heavyweight posted an online Q&A on its environmental targets and also estimated the lifespan of its electronic goods.

Macs and Apple TVs should give its first owner four years of service, while iPhones and Apple Watches will last three years.

The company wrote on its website:
"Years of use, which are based on first owners, are assumed to be four years for OS X and tvOS devices and three years for iOS and watchOS devices".

Apple also offered an assessment of the greenhouses gases that result from its products, stating that 98% of its total emissions come the products it makes:

"We take the same innovative approach to the environment that we do with our products. We’re creating new solar energy projects to reduce our carbon footprint.

"We’re switching to greener materials to create safer products and manufacturing processes. We’re protecting working forests and making sure they are managed sustainably. We’re even creating a more mindful way to recycle devices, using robot".

The company says 93% of its energy came from renewable sources last year, with the aim being to eventually reach the 100% mark.

In other Apple news, the company has confirmed that this year's Worldwide Developer Conference will run from June 13th to June 17th in San Francisco. Details of the event and the planned live stream are available on the WWDC site now.