Originally Posted by
NewbieRunner
No need to collect checked bags in FRA. 1h40m layover in FRA could be tight but they'll put you on the next available flight if you are on one ticket and miss your connection. 1h25m should be fine in both MUC and DUS.
+1
The issue in FRA is that you may have a remote gate, requiring a bus to the terminal, and then it can take a long time to walk from gate to gate in FRA. If its an option, could you connect in MUC? But
NewbieRunner is correct, worst case is you'll be put on the next flight.
No problems on the way back, pick whichever is best for you. No reason to cushion 4-5 hours in that direction, the connection will be pretty easy.