As mentioned above, early on you are fighting swelling, and the sutures are still healing. Too aggressive too soon could cause damage to the still healing sutures. Once you get passed some of that early healing then it is a matter of working your way up to the larger dilators as you tolerate them, and also on personal preference. Some only use the first two and never go any higher. I spent my first eight months using the first three, and only recently moved up to number four. I think the waiting was actually beneficial, for me at least. At this time things are more elastic, as a large part of the healing is done and the tissue has softened. I still start each session at the smallest and work my way up, kind of like warming up for exercising, so I spend about 40 minutes dilating now as I use each one for about 10 minutes. It seems to work for me, though dilation technique varies from doctor to doctor and even from individual to individual, no one is 100% correct, but always best to follow your surgeons directions.