[papuma]

What's the recomended time to replace the shock's and spring's. For some reason I have the figure of 40,000 mile's in my head, don't know why. Was thinking of replacing mine with some new standard Ford ones, not really interested in lowering it. My car is 6 years old with 47,000 on the clock. Was just wondering if it would be worth the expense, better handling etc. or just wait till they fail an M.O.T.

[RobK]

There's no real answer to that. Mileage isn't the factor, it's the type of road conditions, ie potholes, uneven surfaces. A car doing solely motorway miles might reach quite high mileage before needing shocks, while a car driving mostly B-roads may only survive a year if abused.
The test is to push down firmly on the bodywork at each corner of the car over the struts. If the car does not settle after 1 bounce, the shocks are knackered.