Once you download icons from Iconfinder, you have the right to use them indefinitely as long as you abide by the terms in the license agreement. This means that there is no expiration date for the icons you have downloaded and you can use them for current and future projects. However, the icon designer can stop you from using the icon if you break the license agreement of the icon.
Please check the license agreement for each icon before downloading it. All Premium icons on Iconfinder are protected by the Basic license, but you will need to check the license agreement of the non-premium icons. For more information on the different licenses available on Iconfinder, go to the License overview table.
If you have downloaded icons as part of a Pro subscription, you can also use the icons forever, even if you cancel the subscription. However, please make sure to save the icons for yourself before cancelling the subscription. If you cancel your subscription, you will have to re-download the icons by paying for them.