There is no easy answer. I hate if when people just say "it depends", but it does.What is your aim, or your idea of fitness? For health and quality of life, what you are doing is probably very close to perfect. If you want to progress to marathons and ultras, you will have to increase training volume (time) as well. And that increase in volume should be at lower intensities to allow sufficient adaptation without excessive overload. Just my 2c
