Actually, the Sweetwater filter can be cleaned repeatedly and comes with a dedicated brush for just that purpose. There are grid lines that show on the inner surface of the filter element when the cleaning has removed too much of the ablative surface for reliable filtering. MSR recommends replacing the filter when the lines become prominent. Ceramic filters, on the other hand, can become more-or-less permanently plugged by material penetrating below the ceramic surface and away from the reach of a cleaning brush. I have not heard of it happening often but the possibility does exist.

I have used an MSR Sweetwater a lot for four years now with only two cleanings. The grid lines are still not apparent.

I recently replaced the Sweetwater with a Steripen Adventurer and really like the UV system. But, for really murky Arizona water, I will continue to use the Sweetwater.