Per the manufacturer, the unopened Victor Tin Cat Glue Boards M309 - CASE (72 boards) will last indefinitely. Once they are opened the glue boards will remain good for a length of time depending on where you place them. They would need to be replaced if either the board becomes full with insects, or it becomes too dusty which will coat the glue and it will not be sticky. Typically you would replace every 30 days.
The size of each Victor Tin Cat Glue Boards M309 board is 9.5 in. Length x 4 in. Width.
Victor Tin Cat Glue Boards M309 will be effective just as long as the glue is still tacky. Typically you would replace every 30 days.