I dont think their is any such limitation on the workflow timing.
Workflow history deleted after 60 days(be default),after a workflow is completed or cancelled. In other words, Workflow Auto Cleanup only delete the history items for the completed /cancelled workflows.
Workflow history items themselves are not deleted, but the entry point
to view them on the status page for a particular instance will no
longer be available.
Workflow Auto Cleanup job is responsible for this which runs daily.If you dont want to clean the workflow history list, you can disable this timer job.
Disable automatic cleanup of workflow history