One of the Triumph manuals (not sure which one offhand, maybe Haynes?) actually recommends changing rod bearings every 30,000 miles, engine in the car, as preventative maintenance!
I've done it myself, several times. Sure, the result might not live as long as a properly rebuilt engine; but there's no way it dies in 10K miles unless you did something really wrong (or something unrelated happens).
First time I did that, it was on Dad's TR3A, back around 1974 (or maybe 73). Had to do it in the yard, with snow on the ground (my Chevy was on jackstands in the garage). Threw a tarp over the top and a heater underneath, to get things warm enough to handle with bare hands! That engine was still running fine, with no further internal attention, in 1998 when a wheel came off and dealt the final blow to the body. (It was a rust bucket even in 75.) I don't know how many miles it covered in that length of time, but it was likely close to 100,000. At the time it blew up, Dad was using it to commute to work (on a weekly basis) 150 miles each way. So he wanted it back on the road as quickly as possible, even if it only ran 6 months (the end of his contract).
He did mention that it didn't have as much punch afterwards, but I believe that's because I also changed the 4.10 rear end for a 3.70. I figured that running for hours with the tach needle laying on 5 grand had something to do with the swallowed valve. It's also possible that the ruined head had been shaved for more compression.