I am developing a SharePoint hosted add-in. Is there a way (excluding workflows) to change the value of an item from the list after a specific amount of time?
I don't think SharePoint add-in is right solution for your approach.
If you want to update list items after specific amount of time then I would suggest you to go for console application with Managed CSOM. Using this .exe create web job on azure.If you don't have azure subscription then create task scheduler on local server.
following is the link for web Job