Just a heads up, it appears you receive the achievement tied to joining a covenant simply for selecting the dialogue option "Enter Covenant". You may then decline to enter without breaking your current covenant, and still receive the achievement. Maybe this should have been rolled into another thread, but some are getting pretty long now.

**Also, warning!!! The Rare Ring of Sacrifice says in the description that it will cure curse and break when you die wearing it. IT DOES NOT CURE CURSES! It will however break, leaving you to curse the developers/localizers for being dirty lying bastards.

You can join other covenants with out breaking them. You just drop the old covenant for the new one. And then you can always drop that one incase you get bored of it for an old covenant. As long as you don't do anything to break the covenant in the first place you can quit and rejoin as you like.

After you ring the first bell an NPC appears below that will let you leave a Covenant - not sure if this is the 'breaking' people are talking about or not, but it seemed like an easy out.

I've joined and dropped a few so far and there's been no repercussions. I think "breaking" is doing something the covenant specifically tells you not to do, like attacking a member.

Also, the achievements pop as well on 360 just by reaching the Yes/No option.