I don't date my wood or ask it for ID, so I have no idea how old it is. It falls, I cut it, pile and leave it. Some time later, I cut it more, split it and burn it. Most of it is probably old enough to smoke.
The little old cast iron Vogelzang thing will put out some major heat though. Smokes like crazy getting it started or when I add chunks, but once it gets going there is little or no smoke out the stack. I stuff it full, adjust the dampers and wander off. It usually lasts at least a couple of hours between loads.
I have the flue set up where I can take sections out fairly easily to allow cleaning. I get mostly ash out of it when I do, very little black or sticky stuff. I can get on the roof and get the cap off to run a brush down inside. Some stuff up there, but not a lot. Using one of those HF Infrared thermometers on the flue, I can get readings of 200 degrees or more near the stove and less than 100 at the ceiling.
I tried a small tub of creosote cleaning granules from a big box store. Lasted about two years I think. Can't say as I noticed a lot of difference.