Hosea hates, and I mean HATES tummy time. But, he's a really strong boy and is capable of rolling from side to side, and holding his head up and all that jazz, so I don't feel like tummy time is totally necessary for him. We still do it a few times a week, but it's not something I "enforce".
Lately, Hosea has been trying to move, and due to his lack of tummy time, he's developed a sort of wiggle worm/backstroke form of crawling. I find it absolutely hilarious. Something tells me that when he's older, he's going to be one gifted boy at doing the "worm". Check it out.