I always just followed DS's lead with bed-times. This has meant his bed time has changed incredibly over his 2.5 year life. At 8 months it was around 8pm, and at 2 years of age when he was starting to outgrow his daytime naps, it got up to 10:30pm. When we dropped naps, it went back to 9pm. I prefer to just follow his lead as it means bed times aren't stressful or hard work; worked very well for us and i'll do things the same way with our second born.