The longer the threat lasts, the more severe it will be. Likewise, greater intensity creates more severe stress. Failing a bar exam to become a lawyer is harder to cope with than doing badly on a short quiz. The number of stressors will also contribute to the severity. Insufficient sleep is not as severe a problem as it would be with several others added, like a demanding boss and an unsympathetic spouse.
Predictability reduces the severity of the stress.
Knowing what to expect when having surgery, retiring, or getting a divorce eases the pressures. It allows us to prepare in advance. Therefore, it also reduces the severity of the stress. Past experiences can help the person to call on successful coping methods or avoid ones that have previously failed. In contrast, imminence increases the severity of the stress.