Disc machining and bedding pads?

[Bleach1]

Ok i know this has probably been asked a million times but im just after some feed back on this. What are people opinions on machining discs? I have replaces more sets of brake pads than i car to remember but have never machined the discs. Generally if there are grooves or bad scores or so on i have always ended up doing just replacing the discs. Now through my work i know of alot of workshops that simply machine discs as part of a pad change, i dont really aggree with this but some workshops do it.

Also what procedure do people try to do when bedding in say a set of bendix pads?

[TokyoTaxi]

I personally believe that if the surface of the disc is near new, leave it and just change the pads but if the ware area is recessed or there's any scoring, do the machining. I've seen someone put new pads in on recessed discs and try to bed them in only to break away the inner and outer edges of the pads.

Also, I only machine a set of discs once if the car's used for track use etc. I've found that with machined discs and heavy braking they don't take long before they get heat cracks and/or start to warp.

My personal preference for bedding in brakes is to drive the car normally for about 50-100 km and then do some very heavy braking down from 100 kph + to about 20 kph but NOT stopping completely. Instead, I just keep driving so the discs don't get too hot. This is usually enough to bed them in I've found. This is also the way I was taught to bed in the barkes on Ferrari's and Lambo's back when I was a spanner monkey.

Again, this is only my personal belief / preference.