the 350ypvs haynes manual recomend that caliper seals be replaced every two years. and brake hoses every four, irrespective of their apparent condition. don't trust the MOT to tell you whats safe or not. the minimum standard for a lot of brake tests are a joke. brake pad thickness must be less than 1.5mm before you can fail it, and that on a car brake fluid can be as black as you like as long as the levels ok.
i do agree with dave that a lot of stuff fitted to modern blkes is only to get the punter to buy it and of no benefit at all to the road rider. radial calipers anybody