For me daily makes a big difference. If I leave it until weekly my gums will start to suffer for it.

I use the little floss picks, as they're much easier to manage for me than floss, and - here's something - they're reusable. Rinse them off like you would your toothbrush and you can keep those suckers going for a long time. You can also get them made from bio-plastic, so that they'll degrade once they go to landfill.