Yes I do test my equipment or at least pull it out and do an inspection before packing it. My spork is a well used item that I keep in my pocket because I have found it handy in normal life not just for touring and hiking. I don't currently have a tent as I mainly use the hammock (but am planning on getting one and would probably set it up before I leave even if not for testing but for a refresh of set up) but I do inspect the hammock/accessories and if possible I try and set it up. If I had a filter I would probably at the very least inspect it and make sure it would still do it's job.

Basically stuff I use more regularly I don't worry about as much it is the stuff I use less that I make sure to test out or maintain as needed. My touring bike always goes in for a pro-tune a couple weeks before I leave just so everything is good and I can make sure to get some ride time in before hand.
However I was not specifically going after the Sawyer, yes my comment had some grounding in the issues people have had with theirs but was also just a general comment. I believe people should check their equipment, it is not something that is going to hurt anything and it refreshes you on setting up or working the device just so things are smoother on tour.