I have been using the same 1st Generation "black" Sawyer inline filter since 2007 without any problems.
I use it as a gravity filter in camp, I have used it as a staw, and as a squeeze bag with Platypus bags on the JMT for 15 days last year, I have hooked it up to my faucet and blasted the water full pressure to backflush at home, run dilluted bleach through it to clean it out at home, and I have backflushed it in the field by squeezing clean water from the clean water catch bag in my squeeze bag and gravity filter setups....I have even backflushed it while using it as a straw by forcing the water filtered water in my mouth back through the filter.
My filter is still going strong and filters just as good as the first time I used it.
I have a detailed review in the user section here with photos of the inside of the filter to show the hollow fibers (newer ones are sealed so you can not poke around inside to accidentally damage them) and details how I have used it under less than idea conditions.
Yes, freezing is the one thing that can kill this filter, just as it can with any other sort of filter.
I suck the water out of the filter before storing to keep it as dry as possible.
I will then wrap my filter with a small hand cloth that I use like an all purpose wash cloth/bandana and then sleep with it in my bivy bag to keep it from freezing- easy.
The only other way to destroy it is if you manage to break the plastic housing that surrounds the hollow fibers or to snap off one of the inputs or outputs for the inline system, which I had a friend do. (Note: my friends is extremely rough with his gear and is the only guy I know who went light weight and then back to traditional because he was just to hard on lightweight gear).
Great to see the review here and that the Sawyer filter gets the attention that I think it deserves.
Hope there will be an additional review/write up on the Saywer here highlighting useage and tips to effectively use it.
Note: Playtpus bags do not thread well to the Sawyer Squeeze filter and requires modification to seat properly. Better off getting Evernew water bags that use a conventional threading.
Lastly, dropping the filter....I have not dropped mine all that much, but I can tell you that the casing on it is pretty tough. Mine has very visable nicks, scrapes, abrassions, etc...and is completely fine. It is not eggshell thin. I doubt that I could crush it with both hands if I tried to. Then again, I do have T-Rex chicken wings for arms. :)