Barry's take on repotting Sarracenia is not to do it until the roots are literally bursting out of the pots.
And S. rubra sometimes does not like root disturbance: "Adult plants of all subspecies of S. rubra enjoy full sun outdoors. They do best in peat/sand soil mixtures. Make sure you use a large enough pot as the plants tend to not like being transplanted--they don't die, they just take a year or two to get back to their usual selves." http://www.carnivorousplants.org/see...es/S_rubra.htm