It's true that employers are required to offer "reasonable" accommodations so disabled employees can perform the essential functions of their jobs. But that requirement doesn't mean your disabled employees can insist on lower production standards or the ability to work at their own pace. Such requests will likely be deemed unreasonable by a court.
Just make sure you identify up front the job's specific essential functions (in the job description) and keep good records on performance.
Recent case: Jason, a cable company installer, received average-to-poor reviews in his eight years. His most recent review said that he'd face termination if things didn't improve.
Then Jason had a heart attack and went out on medical leave. On return, he requested three hours off for cardiac rehab each week, help with heavy lifting and a "slower pace" to do his...