A "coverage trigger" is an event that causes your Liability policy to pay a claim. There are two basic types of "triggers": occurrence and claims made.
An "occurrence" trigger means that the policy will cover any injury or damage during the policy period. For example, if a roof that you installed four years ago collapsed last week, injuring five people, the occurrence trigger will apply and the policy will pay. It doesn't matter when the roof was built or when the claim was filed - only when the actual injury took place.
A "claims-made" trigger, as the name suggests, focuses on the date the actual claim is made. Underwriting and rating provisions might limit how far into your past the policy provides coverage. However, the key question is: "did the claim come in during the policy period?" If so, a "claims-made" Liability policy will pay. Using the example of the collapsing roof, it doesn't matter when the roof was built or when the event took place, the trigger won't apply until the claim is filed.
If this claim is made during the current policy period, your insurance company will pay it. However, suppose the claim isn't made for several weeks; and by the time it arrives, your current coverage has expired and you're into a new policy period? In this case, the "claims-made" policy will pay the claim, since it was made during the new period.
One type of trigger isn't necessarily better than the other. However, it's almost always wise to keep the current type in order to provide relatively seamless coverage.
If you're offered a Liability policy that offers broader coverage or more attractive pricing - but has a different trigger than your current insurance - consult with us before you make a decision. The only way to be sure you get the protection you need at a fair price is to consider all possible underwriting considerations and how the change in trigger might affect your liability needs.