I'm currently maintain a large project with more than 100000 LOC. The code use the MFC as its framework, in genral, it only has interface part which heavily use the mfc api and a business logic part which full of bad code, confusing logic. The company has some small features delivered to the customer each year(most features are adding code to exisiting project, finding some reference of some api or variable and it' s no different with fixing 3-4 bugs ), most of the tasks are to resove issue and optimize performance . Like other company with maintaining position, it value people who knows much logic about its product. There are people who can quickly finish the job on such project, is it worth to train myself like such a programmer? Is there benifits to work on such project for a long time?