One of the re-occurring themes I've noticed in threads discussing water filters of any type is that they often get clogged and after awhile don't perform as they once did while new or as advertised.

Regardless of what filter type device you use, the idea that some people have and may not be given enough regard in the products instruction manual is the idea that even with a good pre-filter you can just plunk them in anywhere and expect them not to get clogged overtime.
I have a very fine mesh bug net that is as fine as ancient pair of ladies silk stockings.
I put a pot inside that head net and then clear a section of water from obvious floating jetsam and then scoop the pot full.

Yes, I know the real danger is microscopic, but if you can eliminate as much of the particulate as possible before using whatever method fits you, I believe you could eliminate a big percentage of the reason All filter devices lose effectiveness over time.