I have worked with a rider for a couple of seasons now and as an experiment recently we decided to raise their saddle 3mm.
Straight away we saw an increase in power and a decrease in muscle (rectus femoris) discomfort they had been experiencing.
So, despite a bike fit 18 months ago and 12 months racing in the previous position, with good results and development, never think that everything is fixed and no change is needed.
As we get stronger, more flexible or vice versa as we age, our physiological dynamics change. It will be interesting to see how these power gains transfer onto the road this year. But one thing we know for certain is that ‘Nothing is ever Fixed’.