My Cooper lived a life that an engineer would describe as nearly perfect - mostly 30-50 mile trips, so the engine always got warmed through and didn't do lots of cold starts. I would expect this to give the maximum interval between oil changes and I used to get 20-22,000 mile intervals. So I would expect that to be about the maximum.
On the other hand there are Minis that only do 3,000 miles a year (so probably lots of very short journeys) and they will hit the time limit first at two years, so they will get 6,000 mile intervals.
So, yes, 13,000 miles sounds plausible if you are a medium-distance driver. But I wouldn't rely on what the service indicator says just after you've changed the oil. When it's used up half the remaining miles would be a better time to see what it will recommend for you - unless you drove it all the distance from the preceding oil change (or you've owned it from new), it may currently be using someone else's driving habits to work out when its oil will next need to be changed.
PS If you think 13,000 miles isn't enough, do visit American Mini forums where you'll find plenty of guys that think it's madness to run oil longer than 5,000 miles.
Last edited by Angib; Dec 9th, 2012 at 06:13 PM.