Severance offer, what should I ask for? - what worked for you?

I was offered 12 weeks of severance after 12 years as an insurance claims processor, and I have a few days to sign. There is a non-disparagement clause. Did anyone negotiate and succeed?

Read the release carefully. Mine included things I did not expect, like a non-compete.

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.