Never usually reply to non Fabia issues as I run a Fabia myself... But, Yes usually most, if not all manufacturers recommend changing brake fluid every two years. I had a very reliable mechanic inform me that it should, in a sound braking system, with no leaks, really last double that and so a reasonable assumption is to replace it every three years. Cut back a small expense without too big a compamise on safety. A freshly refilled system can all too easily have been insufficiently "Sealed" so as to end up absorbing the dreaded water into it, rendering the whole job useless where a system left untouched for two- three years may have a great waterproof seal. Remember, the cap to check the level has a rubber seal in it... Loosen this and damage the seal, you will need to replace it asap or suffer the consequences! Don't loosen it unless you are sure it needs a top up. This will most likely happen if the brake pads are worn down anyway!

 

Brake "Fade" is most likely with older, lower spec dot fluid, in hot, mountainous terrains or when track racing etc, hence higher spec fluid and brake pads/discs on performance cars. You are more likely to have old, worn flexible hoses "Bulge" Under the pressure of expanding fluid in normal driving.

 

 

I'm going to change mine but; what quantity will I need to do the full change?

Rather than get bogged down on how many miles or years before changing the fluid, just test it.

Testers are inexpensive or your friendly mechanic would test it for you 

 

The job be can be done in 5 minutes.

1 hour ago, johnkitchen said:

Rather than get bogged down on how many miles or years before changing the fluid, just test it.

Testers are inexpensive or your friendly mechanic would test it for you 

 

The job be can be done in 5 minutes.

Testing at the master cylinder will not necessarily give a full indication of fluid condition - but should be sufficient for interim checks. More accurate results would be from fluid extracted via the bleed nipples on each slave circuit.