Its being echoed all around the world: miles will become harder to get each year. Until the shoe drops, I for one, plan to collect all the miles I can. Unfortunately, as someone who enjoys premium cabin travel (and not paying for it) I spend miles a lot faster than I earn them. To craft a few extra trips out of the miles I do have, I try to think out of the box and mix and match one way, coach, business and everything under the kitchen sink.
For starters, even if we are just talking about a simple A to B to A round trip flight don't lump it all into one thought. Break up each leg A to B, and B to A separately. By thinking of each segment individually you can: mix cabin classes, mix airlines, mix miles and if necessary use money to cover a leg. If you have miles with multiple airlines but not enough with one airline this is a perfect way to get around a standard round trip ticket. If your dream is to fly first class and you don't have enough miles to go both ways on one airline, this allows you to book a one way first class ticket and use your other miles to cover the ride coming or going. If you don't have any other miles, no problem, this allows you to find a cheap one way to get you to your destination.
Example A: I love Virgin Atlantic Upper Class. I have enough miles to go one way in first class but sadly not enough for a round trip. For the outbound A to B leg, I could fly a different airline and pay or use miles for a one way flight to my destination. In this case I would probably book a one way flight using cash on Norwegian Airlines for under $220 dollars to London. I could then book a separate one way ticket for my return leg home from London on Virgin Upper Class.
Example B: I have 25,000 miles with American Airlines and 12,500 with Jet Blue. I really want to fly first class one way. I could use my 12,500 Jet Blue miles for a one way coach award ticket to my destination. I could then use my American Airlines miles for a separate one way first class ticket home.
Example C: Even if you stick with one airline to book a standard round trip you can still combine cabin's on your award ticket. On Delta you would need 50,00 miles for a round trip first class flight in the US. If you don't have enough miles, you could still go one way in first and the other in coach for 32,500. If you are at one of those "in between mileages" where you had say.. 47,500 miles, the 12,500 miles you saved is enough for another domestic one way Delta flight.
The bottom line: Get creative. Think of each leg individually and craft a strategy that maximizes your miles and minimizes your cost. Personally, I hate to blow miles on a flight that is cheap to begin with. If you can afford the flight, just book it. Miles are precious and should be saved for emergencies when tickets aren't affordable or luxuries when you feel like experiencing first class without having to pay for it.
As always: firstname.lastname@example.org