If your LO is a good sleeper, do you think it is 100% luck or do you credit some of it due to you helping create good sleep habits?

My 20 month old is a great sleeper but it took us some time to get there! I don't take 100% credit for these habits because I do think a good majority of it was just how she is but I hate when people act like it was just a pure luck that we got a good sleeper. They obviously weren't around the first six months of her life! Anyways, with baby number two coming next month, I keep getting comments about how he is going to be a horrible sleeper and just a complete terror because our daughter is such an easy baby. It drives me nuts. I plan on doing the same type routines with him that we did with my daughter to hopefully create some good sleep habits for him too. But I am prepared for a horrible sleeper because I think I was pretty lucky with my daughter.