[One of the great advantages of net fora is that you can disappear embarrassing posts, which is why the opening paragraph of this post has gone poof! after the excellent MacSpud tipped me the nod.]
There's another consideration that shouldn't be overlooked. If your wife's bike has an eccentric bottom bracket, is it correctly done up, or has it shifted? Same story if her Rohloff is fitted to a slotted, sliding rear end: have you, or the mechanic, done it up right?
I take it you are aware that the chain pulling a Rohloff is run quite a bit slacker than derailleur types or even other hub gearboxes.
Also, a Rohloff chain is supposed to run perfectly parallel to the frame's centreline, the so-called chainline. If it is off, the built-in sideways play in a derailleur chain may give superior wear, whereas a fixie chain will bind and wear faster.
