I suspect very few weekend pilots routinely do W&B checks unless the loading is different to normal, in which case you would hope they would. I certainly do when heading off on a long trip and loaded front and back with a lot of extra stuff plus full fuel, but I don't when flying solo locally. I visually monitor fuel usage and fuel flow on every flight, but don't record it for local flying. I do on a longer trip. Of course as with everything, unless you do the paperwork regularly you get rusty. In fact, it wouldn't do me any harm to get my BAK and PPL books out again and get back up to speed, and I'm probably not the only one.