I no longer need condoms for birth control (I have an IUD) but my partner does usually use a condom for anal. I sometimes ask him to use a condom for vaginal sex if I am going out afterwards, just for neatness.
We do, for birth control. I can't take hormonal birth control and condoms are easy enough to deal with. We don't always use them, but most of the time.
We don't, actually. He pulls out when he gets close, then finishes externally. We've tried condoms, but they either hurt me, or they're fitted awkwardly. I don't like the idea of using birth control -- I'm not one for taking in too many foreign substances unless my body absolutely needs it, especially not substances that kill off the things inside of me.
My partner and I typically don't because we're fluid bonded. We have had many discussions on our safety, both been tested for STIs, and both are well educated on the risks (that's actually what I do professionally). If one of us has sex with someone else we practice safer sex- condoms, gloves, oral dams- we're very committed to our (and one another's) health.