at around 25K miles. 225K miles later the seal is still oil tight.
Find the best car you can afford and test drive it (at least 30 miles) then have a PPI done that among other things looks for any signs of the RMS leaking (though of course the PPI wants to look for *any* fluid leaks) and if the PPI comes back on the car good then buy the car.
Sincerely,
MarcW.