I do consume around three large coffees an average day. I would get a headache from caffeine withdrawal (not a migraine though) so it's been a pretty long time since I've really gone without caffeine.

Couldn't say whether caffeine is negative or positive as it's pretty much always been a component.

I stopped taking caffeine because of a problem with anxiety. My migraines have remained. I do find caffeine helps with the pain of a migraine though. I think sudden reduction in caffeine intake can trigger migraines...