Since most of my car have been Jag/Merc and BMWs no exhaust issues. I currently have a 4yrs old ford and Merc, have to see how they go.

Modern exhausts last almost infinitely longer than those from the "olden days" - better materials, better design and very controlled gas composition means that modern exhausts are far more likely to corrode from the outside in, rather than fron inside out.

I had hoped it would have fallen off by now, but my Saab's exhaust is 10 years and 100k and completely original. I had a look while it was on the MoT ramp a few weeks ago - still no signs of it giving up.

You might find the outer skin of the rear box flakes off (it's almost like double glazing, with two distinct layers of steel with a gap between), but it doesn't really matter as it's nothing to do with the box being gas-tight. Bits of mine were falling off for years! The last bit I pulled off was about 6" by 12".....

My Subaru Legacy/Outback 2.5 petrol has the original exhaust system and it's coming up for ten years old and 103,000 miles.

This is quite different to all of the cars I have owned previously. When I lived in Zambia the exhausts and silencers were not on sale. If you needed a replacement it was by arrangement with a welding shop. Any steel pipe would do. My friend had a Ford Zephyr and he himself made the silencer from a 4 inch pipe. It sounded a bit hollow but not unduly noisy.

Any thoughts on what type of steel is used ? did a quick google and found one site saying SS 409 is the general choice, but same site states ss 304 is sometimes referred to as 'marine grade', which I thought was 316. ??

Back to topic;

1999 (June) Passat still original exhuast at 187k miles, coming up to 17 years - not bad. Same clutch, etc. only servicable items changed; disks/pads, batteries...

I can’t beat the OP, but a 2003 Leon TDI on 100,000 miles with the original exhaust. Last year had an advisory on the MOT that the back box was about to fall off. Took a look and it was the heat shield and I pulled off what was left of it. Just had another MOT and there was no mention of the exhaust. Actually a straight pass with no advisories, not bad for a 13 year old car.

Our 2007 Mazda 1.8 petrol failed its MOT yesterday and is having a replacement exhaust fitted today. I guess you win some and you lose some!

But this is the first exhaust I’ve had to replace since the mid 90s. I think the quality of exhausts have changed since catalytic converters were introduced. My first couple of cars were pre-cat and needed new exhausts before they were five years old.

Having had a couple of Rover TDs over the years (200 and 25) I found that the exhaust from the engine to the rear axle lasted with little or no corrosion. What used to go was the back box, that section would swan neck over the rear axle and the spray from the drivers side rear would always rot the weld where the 2" pipe went into the silencer. I'd be changing the box every2 or so years due to corrosion. Not too onerous to change out, could be done from the roadside with no pit, jacked up with the rear wheel off, but getting the new 2" swan neck over the rear axle was a b*****.

One of my work colleagues had a winter and summer exhaust for his renault 16. once the winter ws over he removed the exhaust and sprayed oil inside to counter the rust. he then fitted the summer one.

when the floor rotted out he mixed up a gallon of araldite and poured it into the remaining parts of the floor!

This chap must have been a seriously splendid fellow!