Seaecho - Just because a plant has been in the same location for several years and is not dead, does not necessarily mean it is getting adequate light. Your Croton should be close to a completely uncovered window.
The conventional wisdom about regular repotting is based on informant from professional nursery growers, who should know, right? Well, they are right, but only for the ideal conditions they maintain in their greenhouses. I take care of plants in hundreds of homes and offices that have far less than ideal conditions. In those environments, plant growth rate - especially in the root zone - slows considerably. That means moderately mature plants in pots 8 inches and larger rarely need repotting or soil replenishing as they would in a greenhouse. As mature plants age indoors, their growth rate slows and so does their use of water and nutrients. In most instances, it is best to do less rather than more, especially when it comes to repotting.
