If it is optional, but the employee does not contribute, the company generally does not contribute either. Some companies will pay for part or all of an employee's schooling to improve knowledge or skills in the given field. This is a benefit that would provide income to the employee or surviving family if the employee dies or becomes disabled. This money will deducted from each check. This is probably the most important benefit to workers.
Health insurance pays for the majority of medical costs when a person is sick or injured.
Most employees need to pay for part of the monthly premium that the insurance company charges. It is also important to point out that an employee who only wants herself covered is going to pay less than an employee who wants her whole family covered. Health insurance is sometimes offered to full-time employees. When starting a new job, they understand the benefits that are offered and are able to ask the benefits coordinator questions when they are confused about a benefit.