Originally Posted by
Steve in Olympia
I don't think there are any advantages of redeeming Avios as returns, apart from having fewer PNRs to keep track of.
There is one distinct advantage of booking return flights: on a mixed-class trip, you get the highest baggage allowance from either the outbound or the inbound.
Another is that the cash element can be lower if you book a round-trip ticket rather than two one-ways. This is because of the way that TFC are calculated - or more specifically, I think it's the fact that the YQ surcharge can vary according to the start point of the ticket.