Brake fluid is hydroscopic, it absorbs moisture.
It is important to keep the cap on the brake reservoir tightly; and any brake fluid you may have at home.
If the brakes are 'spongey', need pumping, I think a brake fluid change will improve the braking efficiency.
Furthermore, brake fluid that has absorbed moisure can be very dangerous.
Under severe braking, the brake fluid will get hot, and the moisture absorbed within in it can boil.
The nearer the moisure is to the disc, the higher the tendency to 'boil'
You cannot compress hydraulic fliud, or water (but you can increase the pressure of both), but water vapour can be compressed.
Changing your brake fluid is not expensive.
If the brakes have a better feel it's money well spent; if they don't at least you know the fluid is not the cause.