I see a lot of your babies where sleeping at an early age, mine took longer (finally at 9 months after 3 months of sleep training) to reach that STTN stage but now she is waking up again more frequent and I'm afraid to return back to the old days with barely sleeping periods. So I wanted to know if eventually is an age when they stop needing your assistance at night, but I have an idea now!
I say, trust your gut. That is my issue with sleep training, for US it feels wrong. Plain and simple.
If I had done it, sure, my son may STTN now, but I keep hearing that babies need to often be "retrained" due to teething, or other disruptions like growth spurt, learning a new skill, travel. It's not for us.
If it feels right to sleep train again, do it. I personally have never asked my pedi for advice (nor has he ever asked how my son sleeps) and I think you just know as a Mom what feels right for your particular child.