With daily or frequent use, accessories will be prone to wear and tear.
A decrease in pump suction may indicate that the accessories are worn out and it is time to get new accessories.
For normal daily pumping, accessories can be changed every 2-3 months or when a decrease in suction is present.
The part that would be most prone to wear and tear would be the valves. Expect to change the valves about every 2 months.