The Senna Extra didn't even work for me, I took them 4 nights in a row, then resorted to dulcolax. Every 2 or 3 days I take one and night and go to the toilet the next morning. I definately wouldn't go without taking one though.
I take linseeds-a couple of tbsps every day and that seems to work. If I have any problems I also use Dulco Ease. Hasn't been so much of a problem since I started having a bar every day.