What context window configuration do you use with the latest models and latest codex-cli?

I've been using Claude Code heavily for development for quite a while and just recently switched over to codex. I use these on some pretty complex cross domain codebases and the 1M context window definitely helped on Claude Code.

I primarily use Codex CLI and realized that even the highest tier models come with a 256K context window by default. Anyway I changed the config to switch 1M context window on and I've got no complaints so far. It does burn the tokens quite fast when the context gets expanded during long running tasks.

But I want to know the experience of using the default context of 256k on complex projects / long running sessions. Does newer models combined with latest codex-cli harness automatically manage this in some efficient way that we shouldn't actually enable 1M context? Im wondering if thats the reason for OpenAI shipping their frontier models with 256k by default.

I would like to know others experience with this. Thanks.