This is my first season using my 5036.  I don't really have a feel for the amount of ash I should expect.  I've been burning just under 2 months so far. 
After the first 30 days (+/-), I completely cleaned out all the ash per the manufacturer guideline.  
It's been about 3 weeks since the full cleaning and I've got quite a build-up of ash again.  Here for the last week, I've been regularly taking a few shovels full (enough to fill a small 3 gal metal pail every other day) out and that seems to be dwindling the pile down. I'd say a good portion of this ash is dust too - I rake the chunks of coals around and let them burn down. 
Does this sound like a normal amount of ash?  I'm burning decently seasoned wood; mostly maple, black cherry, locust, and a little white oak.
Also, is this a good practice?  I have a decent coal bed and ashes under that still.  I have noticed that the ash dust that I pull out retains a good amount of heat too.  The metal pail I dispense into stays warm for a couple hours after I fill it; should I instead leave the ashes in the furnace?