YouTube : http://youtu.be/6dtNiakSS_g
My son is 6.5 months old and started crawling. He still gets around primarily by rolling and the occasional army crawl. At my house, I only allow my son to crawl in certain places – either the living room or his nursery. Besides that it’s just not clean enough for my liking. I never allow baby to go on the verandah. He crawls everywhere except for the bathroom. I just supervise him closely and wash his hands as needed. Also, we don’t wear shoes in the house so it is pretty clean anyway.
He started crawling when he was 6.5 months and started walking at 9 so I do think it has helped his development to be able to explore his environment.