Thats what happens when they dont are fighting Dracula:
Video Game Confessions - Simon BelmontIf we use the in-game logic, they gain their money from monsters and selling things. If we use normal logic, they battle monsters and gain the money in the same fashion anyway. Now, if we use real world logic, exiled Belmonts are like rangers, protecting the forests and wild places (that are their actual home) from evil beings and people. I dont think that these specific Belmonts had a specific task to be treated as a job, since they will need to know to do all sort of things, like hunting, wood-cutting, fishing and etc.