I restrict entries to models I have not brought to that show before. I do not build a model for a specific show, ......... But it is a general show model, for any show. I will enter it in all the shows in the area once, then retire it from competition.
One exception is a theme award. I may pick a kit to build specially because it fits a show theme well, whereas I might not have built the kit otherwise. I like to support themes at shows.