I have a sta-rite system 3 as well and just wanted to make a couple of comments on the thread:
1) Other problems could result in quickly rising pressures as well. Last year when I had this problem, someone suggested that I might be on the verge of an algae outbreak (algae growing and being killed off before I really ever saw it). At their suggestion, I elevated my FC to 8-9ppm for a while and the filter stays clean a much more reasonable period of time now. When I was having this issue, the stuff I was rinsing off of the filter was kind of a grey slimy stuff. Just be aware of other potential issues before going out and dropping $5-700 on another set of filters (I don't know how big yours are, but that's about what mine seem to run. (my filter is only 3 years old so I haven't replaced it yet).
The scenario i described (earlier in this post) is with nothing drastic being done to the pool afterwards, i.e. trying to kill off an impending algae attack. Of course this will send more material to the filter and cause a premature pressure rise. My bad for not specifying. However, I would try to kill the algae off before i clean the filter. This way, you only have to clean the filter once.
2) My restraining bands started coming unglued almost as soon as I had the pool installed. I found that hot melt glue seems to work really well for re-attaching them. The "restraining Bands" are mostly for manufacturing, they help hold the pleats in place as the top and bottom pieces cool/bond to the element.