I've been burning pine (actually a mix of different softwoods, probably some pine, some fir, some spruce) since late September exclusively. This is waste wood from work, 4' long 4x4s I cut down to 16". It's good and dry, burns hot, and leaves almost no ash. I really like it for this time of year. If need be, I can fill my big firebox on the old wood furnace full and get 8+ hours with it damped down, or get a quick warmup out of a 1/2 full firebox running hot and fast. I have an outdoor clay lined masonry chimney (aka creosote factory), but with the usual smaller hotter fires, it's cleaner than it would be burning hardwoods damped down.
Someone made a comment in another thread about this being something "poor people" did. I'm not independently wealthy, but I know that free wood that would otherwise go to waste, that takes almost no time to process and burns great, makes me more wealthy by not burning "good" wood when it's not needed, and keeping the furnace off. Ron White said you can't fix stupid, I'll add that ignorant is tough to deal with as well.