Ok, so I'm looking at taking the plunge, but I want to know more first ...

What cup do you use?

Why?

Do you have multiple sizes, or just a medium / large one that you change more often during heavier flow?

What on earth do you do if you need to change it in a public bathroom or at work?

How long do they last (as in years)?

Do they come with a storage case, so you can pop it in your bag in case of surprise periods?

Can you wear them overnight (as long as you're sleeping less than the 10 hours allowed)?

Do tell ...