Many of the disadvantages with the occurrence trigger are based in the fact that there can be significant difference in time between the time of the occurrence of the claim and the time where the claim is actually filed on the policy. A problem with the occurrence trigger can be to actually define when the claim occurred. An example of this is continued exposure to a harmful condition where there is no definite time where the damage occurs. Another example is where a machinery has been serviced, repaired and generally worked on a number of time, and it is impossible to define which of the service visits actually caused the damage. This insecurity in defining the time of occurrence can also cause the insurance companies to spend resources on trying to define which policy period is relevant and who is covering the claim instead of spending the resources on actually handling the claim itself.
The Insured limit can be deflated by inflation, the insurance company may not exist anymore and the coverage of the policy may not match the juridical environment that exists when the claim has to be handled. From a more practical point, the policy can be lost and the Insured can have a problem with remembering and proving who they were insured with and on what conditions on the time the claim occurred.