To clarify the statement about "stacked" insurance policies:  You Can buy multiple disability insurance products.  However, they cannot provide you more income replacement than your pre-disability income -- They may coordinate or blend your payment so 100% of your pre-disability income is replaced.    Most private policies allow for additional insurance purchase, as your income increases, periodically over the duration of the contract.  So the most common example is an individual with a group policy who needs a second policy to supplement the group policy, so his or her pre-disability income is replaced up to 100%....Some group policies terminate after a fixed duration 5 years for example, so it is important to know all the details of your group policy before purchasing a private plan.  In that case, it would make absolute sense to "overinsure", making sure your income was replaced 100% in the event your disability was prolonged > 5 years.