@adam-
Not sure how much of the 1M context window I used while collaborating with sonnet 4.6 on dedicated project for a month straight, but it saved my bacon when somehow all the work we had done was wiped.
When I asked what happened it said didn’t know, but could recall it all from memory to recreate it.
At first this was big enough where it would fail. I then asked it to break it down by segments and it successfully recovered everything.