I rebuilt mine and reused all the fittings and bolts.
About 1000mls later one of the cup washers that need turning though 90 degrees to lock failed, the centre pulled through and locked the back axle solid. Luckily I was only reversing out of the garage at the time, needless to say I replaced all four for new ones pretty sharpish.
My car only had 22,000mls on it but the wheel cylinders needed replacing as they had leaked and contaminated the linings before I owned it.
Another good reason to change the brake fluid every two years.
