It’s just a guide, every baby is different. I’ve not noticed my baby have the sleep regression she’s been waking up 30/45mins earlier some days but I think that’s due to her teething 🙈
My baby does not agree with Wonder Weeks app at all. It says we have 2 days of fussy stage left but he hasn’t been fussy for well over a week as for whether he is going through a sleep regression - no idea because he has always woken up several times a night. Been a couple of times less recently so maybe he has been through it and out the other side 🤷♀️
If it helps my little girl still has 7 days left of the fussy phase of leap 4 and i havent noticed her be any different or any changes in her sleep. My first always seemed to be a week ahead of their prediction x