Severance agreement arrived, need a second opinion - what worked for you?

I was offered 12 weeks of severance after 12 years as a copywriter, and I have a few days to sign. I have read a lot of threads here and could not find my exact situation. I do not want to leave money on the table. What did you ask for?

An hour with an employment lawyer cost me a small fee and made me feel much safer about signing.