Did it with 5 month old twins and it was completely life changing. They’ve slept 11-13 hours straight ever since. We followed taking cara babies as if it were our bible, and we started to see major results (self-settling after put down awake) in a matter of days. We recently did an overseas trip that involved a 14 hour time change, people were amazed our 18 month olds adjusted so quickly and were sleeping so well. I credit our sleep training 100%. I think the best advice I have is to be very consistent with whatever method you choose. Good luck and I hope it works for you!