When I had my first child I had many disagreements with my elders as to the right way to raise my child. Silly stuff like pacifiers, how to put her to sleep, bath soap, etc. I was busy doing research, reading and talking to other parents to make a decision on what should be done. But these elders always felt like I should listen to them and their expertise, after all they too had raised children.
Recently I was reading an article about starting solid foods. I was shocked at what the article had to say. It was the opposite of everything I did with my daughter, just 3 years ago! No longer should solids begin at 4 months, but closer to 6 months and the first foods should be veggies or fruit instead of cereal.
Its amazing how the recommendations have changed so drastically in just three years. I don't know how I feel about that since I started both of my kids on rice cereal at 5 months and they seem just fine. So now I sound like my elders chriping, "my kids grew up just fine" and ignoring the experts.
But its important to stay educated and continue to listen to your pediatrician. Don't just assume you know everything because it is your second or third child.