Technically mine has never left me by the side of the road, except when the clutch arm snapped, probably could have limped it home but it was quite a way, so not worth trashing the gearbox for (turned out it was knackered anyway) The lift pump failed a the end of the drive one day so doesn't quite count-though didn't make it to work that day.
The trouble is with defenders is they need a ridiculous amount of maintenance to remain reliable. the Since buying a 1995 300tdi at 136k, I'm now at 148k and have replaced tonnes, Gearbox, all suspension, lift pump, rear diff, rebuilt front hubs, usual prop uj's, steering box, lift pump, fuel tank, bits of wiring, brake servo, clutch. After all that I'm only just beginning to feel like its up together and still have to thump the starter motor with a hammer occasionally as the solenoid on that is now packing up.
Yes were dealing with a 17 year old vehicle but I had a mk2 crx vtec with more miles and even older that didn't put a foot wrong in 2 years!
Having said all that, despite the pain and cost i wouldn't be without it.