Originally Posted by corporate-wage-slave

It's all a bit relative. But usually reducing the cost of a commercial ticket using Avios isn't good value, the clue to this is the fact that BA makes it so easy to do this. There are some exceptions though.

If you have a decent hunch that Avios seats in CW are going to come along, but you are actually fine with WTP, your best bet is to buy WTP as cash, check every morning via a dummy booking (or other tool) to see if CW has popped up overnight, then you should be able to online upgrade to UuA, or call up to do so. Make sure you know what the UuA taxes and fees amount should be, roughly, the online tool often seems incorrect. Over time you may also be offered POUGs, if it's a simple LHR-DXB booking, and you can weigh up if to go ahead with that. So you have two tracks open to you. Plus AUP at he airport.

As an alternative, if WTP availability is showing now, but not CW, then make a straight redemption in WTP now and if CW shows later then you can easily amend the booking to CW, with a £35 per person change fee.

If you really want to go CW, don't fancy the chances of the upgrade showing up (e.g. school holidays) then consider a CW purchase and reducing the cash amount with Avios, even if this isn't good value.