[dragonwriter]

> Why limit the amount of days your allowed to be sick?

The number of days you are allowed to be sick is not limited; the number of days of paid leave to deal with being sick is limited.

> What happens if you are sick for more days than what your contract allows?

Depending on the nature of the illness and other factors, you may be eligible for unpaid (by the employer), job-protected leave under FMLA or similar state laws, and may be eligible for disability payments during that leave under state law. The employer may, even if that law does not apply, extend paid or unpaid leave beyond what it is committed to in your contract, but is under no obligation to do so.