Car insurance question

How(or when) do people make the decision to switch from Comprehensive auto insurance to just Liability? Posibilities:
1 – when the car is paid off(not that many here would voluntarily do car payments)
2 – when the car is x number of years old
3 – when the vehicle has x number of miles on it
4 – when Bluebook value drops below $x
5 – when you have enough money in your car replacement fund to purchase a replacement

Any others I’m missing? My current vehicle is a 2003 Malibu with about 220K miles on it. Bluebook value according to is about $2900. I’m surprised it’s that high because of so many miles.
Although, that averages out to less than 22,000 miles per year…
I don’t have ANYTHING in a car fund – still trying to build my FFEF.
That’s going slowly because of unplanned expenditures, along with some frivolous spending as well. My recent auto insurance renewal was $588 for 6 months, or $98/mth. Debating how to proceed, and I’d be curious to hear others’ opinions…