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) post 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 fledge story in the post Breaking Bad world.
“We couldn't really give you an exact amount of episodes," Gilligan told us. "The reason being—and I'm not being coy here—it’s just hard to know exactly. But you did put your finger on something important. Just from watching this show you can tell that it's a finite story. And we know that even further from the fact that this show has to butt up against the beginning of Breaking Bad. So there is a finite nature here.”
But there's one difference in Better Call Saul’s finite nature that wasn't there with Breaking Bad, which is that there is yet again the possibility of a whole other story to be told through the black-and-white beginnings of a post-Breaking Bad world that we've put at the top of each season," Gilligan says. "So while I think that there is a definite end in sight for the pre-Breaking Bad story, there still seems like there could be a lot in the post-Breaking Bad world. I'm kind of fascinated by that, simply as one of the first fans of the series. What could come out of that? No promises, but it seems to me that there's a little more opportunity for scope there than there even was in Breaking Bad.” http://www.denofgeek.com/us/tv/better-call-saul/264179/better-call-saul-could-become-breaking-bad-epilogue-vince-gilligan-reveals
Season 4 However, has been teased to go right up against Breaking Bad, including introducing more characters that were mentioned in Breaking Bad, but never before seen.
“This is the best season yet,” Vince Gilligan told Comic-Con today of Better Call Saul’s fourth season that starts next month. “The overlap between Better Call Saul and Breaking Bad gets closer and closer,” added the creator of the Bryan Cranston-Aaron Paul Emmy winner and co-creator of its prequel of sorts, driving the cavernous Hall H crazy with anticipation.
“You are going to see some stuff,” Gould cryptically declared before showing a clip of the Bob Odenkirk-portrayed slimy lawyer who first appeared on Breaking Bad in its second season in 2009. “You want the last hill on the rollercoaster to be the scariest of all,” Gilligan added. https://deadline.com/2018/07/better-call-saul-breaking-bad-crossover-tease-season-comic-con-panel-trailer-video-1202429718/
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.