Originally Posted by Alsace

I am flying on Emirates over two legs, both economy, booked through Emirates' site, and it's the return flight of a round trip.

BKK > DXB (6 hours on a 737)
DXB > JFK (14 hours on an A380)

I've been offered the ability to buy an upgrade to business class (via likely-automated emails) for $650 and $1000 for those legs, respectively. That's out of my budget, and between the two I'd prefer upgrading the first leg because the 737 is cramped and I'd like to sleep. (I know the A380 business is very nice, and it's a long flight, but honestly economy is unusually roomy.)

If I buy the upgrade for the first leg, will it help my chances of getting a free/discounted upgrade on the second leg? I've read about people being upgraded when they intentionally booked different classes for each leg or got lucky and got upgraded on one leg. I have no FF miles or any sort of rewards/loyalty to use.