One of my first Moteino projects, a bme280 weather sensor, mounted in my crawl space. It is still running, on the same charge, after 4.25 years! I don't recall the size of the lipo battery I used. I figure sometime next year I will need to crawl under there, after it signals low battery, and charge it back up.
Ha, same here with an attic node, ran about 5 years before it dropped out. That's considering the extreme temperature swings (up to 130F in the summer, and down to even sub zero F in January-February/Michigan), not bad I'd say. And that was with a traditional Moteino R4 with LDO, 16mhz. Could have squeezed more without the LDO and running at 8mhz. The battery was a relatively small 1500mAh rated china LiPo, who knows the real capacity..
So now I want to see ESP boards users brag :o