I'm fairly sure I'll be in the minority about this discussion regarding DE maint frequencies.
I'm located in the Dallas TX area.
I Backwash my 36 Sq Ft Nautilus (Pentair) Filter about once every 3-4 months. I've been able to go 6 months between Backwashes a couple of times during the past several years.
I have a Pecan Tree overhanging my pool so I also receive seasonal pollen, pecan buds, leaves, etc into my pool.
Before I switched to TFP methodology in June 2014 (Bleach dosing with FC/CYA ratio monitoring), I had to Backwash using the 'pool store' rule of thumb, ie, once every month or so.
Since using TFP methods, my Backwash frequency has decreased significantly.
The last time I pulled the DE Grid Assembly for a complete cleanup was Sept 2013.
I monitor my PSI reading regularly, recording 'pre load' (after Backwashing & before loading w/new DE), and 'post-load' PSI readings.
I have gained ~1 PSI since Sept '13 from a 'best-case' starting PSI reading (PSI reading with a new Grid Assembly installed prior to loading with DE).
I have a working TFP Glycerin-filled 0-30 PSI Gauge on my DE Tank.
So far, I've not seen the need to pull my DE Grids on a timed basis. I realize this isn't the forum recommendations and I'm not disputing the recommendation in any way. I'm just providing my experiences as a DE filter pool owner.
I've never used Cartridge or Sand filters so I have no experience with either filter type with my pool.
As other members have said, it's a matter of personal preference.