I'll admit I haven't taken my DE filter apart for about 3 years now, mind you I only backwash and recharge the thing once maybe twice per season. I have a mesh safety cover and more laziness stopped me from adding chlorine during the winter, so I started with basically a swamp this years. The filter just wasn't working as fast as in years past, so I broke the thing apart and man I wish I had taken some pictures. It is insane how much DE is left behind even after a vigorous back-washing session. There were just huge clumps of DE some almost top to bottom in between all the inside grids, so please take the word of a lazy guy, get off your butt and manual clean your filter at least once per season.