Gasoline can only leave deposits when it evaporates. In a closed system, that is incredibly minimal. Lawn mower stored for the winter? That is the other extreme. Pretty rare for an injector to get gummed up (if ever), especially direct injectors. Think about the pressures involved. Injectors are more likely to suffer from wear. There is nothing else that can get gummed up.
2018 Kia LX HEV Metal Stream with Advanced Tech