Conversely, ramp-up time should not be infinite. A junior employee should not be limping along after a year at the company. Either that person just isn't a fit, or there is something terribly wrong at your company.
As a step before firing for a junior employee that shows any sign of promise, a 3-6 month performance improvement plan with regular check-ins and measurable progress points could make a world of difference. I currently have multiple juniors on PIP's and they are taking them very seriously and improving less than acceptable behaviors.
