I am not pumping very often any more, but when I do, I am almost always getting milk in the tubing of my PISA, which didn't used to happen. Is this an issue with the tubing, or the pump? My pump is over six years old and has been used heavily (I used it to pump while working full-time for babies one and three, and as my backup pump for baby two.) Other than the milk in the tubing, it's working fine. I'd like to prolong its life for as long as possible - I definitely don't want to get a new one at this stage of the game! Is milk in the tubing deleterious, other than the effort it takes to clean it out? It looks like the tubing is not too expensive to replace, but I don't want to spend the money if it's just going to happen with new tubing anyway.