A lot of it seems to depend on what's going in and how its allowed to build up. White oak seems to leave very little ash. It all falls through the grate and disappears. Silver maple leaves a lot of ash, but ends up about the same as oak if allowed to build up and compress. Lite and fluffy, then not. Either way, I can leave the stove alone for about 2 weeks or so if I'm not pulling the pan to clean.
We have backup heat, but it's set at 64, so downstairs did get down to 64 this morning. It took hours to burn down with the door cracked open and raking things up once in a while. There were still some glowing embers when I finally emptied it.
If you have post oak cut them a year in advance and let them lay. Come back year later cut and split and bark will normally peel rite off. Lot less ash and makes post oak even better firewood. Great fence post as well hence the name.
I had some interesting experience this first year of burning when it comes to ash production. When it was in the single digits I was reloading with a pound or two of hot coals left to keep the house around 72°F. After a while the box was full of bits of small coals that had been covered up and cooled off. I was emptying the ashes at least twice a week. Now I have been letting the stove cool into the inactive cat range with the same white oak and I'm pushing 2 weeks with about 1 pan of ashes.
Also running through my norway maple stash I was draining ashes about twice a week. It produced lots of large chips and coals left.