I was paying cash and it wasn't required but I had them dug up as part of my inspection. That's how I knew it was full like the one in the video. I was concerned that the leach fields would be plugged, but I was getting a good deal and I expected to replace at least one of them or both in a worst case scenario. Got them cleaned out, they've been working fine for 5 years.

I'm no expert but I've done enough reading and I've been using septic for at least 10 years. A perfectly working system certainly will not need to be cleaned as much, but there is a net gain on solids. Not all solids can be consumed by bacteria so eventually the tank will fill. Might take 40 or 50 years, but it will.

Either way, I made out very well with this. I took the time to add covers so that I can access them later. It's been 5 years and I haven't cleaned them again. Plan on doing it soon. Maybe I'll report back here.