Maple syrup vaccume tubing
Maple tubing is usually replaced every 5 to 7 years. There is no "shelf-life" for tubing and certainly some folks will use it for longer but on average it's about 7 years. Keep in mind, the longer you use the tubing, the more it degrades in the sun and the more mold can develop inside the tubing system.
I see you are located in Vermont. A great resource for you is UVM Extension. They have a maple specialist available to the public to answer any questions. His name is Mark Isselhardt and he can be reached at 802-889-9926.