At this point it is hard to know, because Better Call Saul is mostly a prequel, but each season also opens with a scene (shot in black and white) postclose to the end of Breaking Bad. It's unclear if Better Call Saul will eventually recover parts of Breaking Bad and/or if later seasons will jump ahead and tell a full fledgefledged story in the post Breaking Bad world.
##UPDATE - Future Scenes: Upon
Upon the new "future scene" in episode 4.01's opening sequence, it has been suggested by Vince Gilligan, Peter Gould, and Bob Odenkirk that these future scenes may take place right before the end of Breaking Bad in between episodes 5.15 & 5.16. Also Episode 4.01 features an uncredited cameo from a well-known Breaking Bad character. Tonelly there is also a shift in mood, which is most likely closer to how Breaking Bad feels in comparison.
##UPDATE #2 - New Movie:
As it turns out there will be a feature film that takes place post Breaking Bad, featuring the character Jesse Pinkerman.
Not much is know about this yet, including if 'Breaking Bad' will be included in it's title or if it will get it's own name, but more over it doesn't also explain what this would mean for Better Call Saul's future either, if that character will end up in this film or if Jimmy McGill will still also go on past Breaking Bad on the TV series or if it will stay more strictly a prequel?
I'm someone who has not seen more than the Pilot of Breaking Bad, but I do know some spoilers/character arcs. I know that most likley Breaking Bad viewers are getting a lot more out of Better Call Saul then I am, because there are a lot of easter eggs and such, but I have decided to wait until Better Call Saul is over and have the opposite experience, as I enjoy the show greatly without knowing every little detail of Breaking Bad.
AMC just renewed Better Call Saul for a fifth season. If I were to guess, I would assume given what has been said about season four, that if they were to jump ahead into the post Breaking Bad world more ardently, season five would be the start. Personally I love the idea of Breaking Bad ultimately fitting into Better Call Saul, as opposed to just a companion piece or a prequel.