If the bad pulleys fail or cause a belt to snap you can have major overheating problems on a road trip.
I do tensioners when I do pulleys out of habit, but I don't know that you have to.
I've found with BMWs it's better to fix small things like this before they totally fail and become big headaches.
Now Coding Cars in the Burlington,VT/Plattsburgh, NY area - PM if needed
BMWCCA # 461124
1986 325 - SOLD
2002 325ci - gone :(