I don't want a nudge. I want a clear RED WARNING with "You've gone away from your computer a bit too long and chatted too much at the coffee machine. You're better off starting a new context!"
I think after the TTL expires the session should be autocompacted and the user should given a choice to continue with compacted version or be hit with the full read cost of continuing with their large but expired context. At the moment users are blind what is going on.
Why is nobody even asking why that should be an issue? No other text editor shits the bed that way. The whole point of the computer is that it patiently waits for my input.