I think I just propped DS up with some pillows around him, but he was normally more happy on his tummy and getting up on his hands and knees - this was from about 5 months. He finally sat up on his own at 7 months and crawled just before 9 months - so it could take AGES..... I say just take a little bit of info from everyone and then make the decision that feels right in your gut. Use your instinct. It won't be wrong.