For me, no significant miles will get saved for retirement. They devalue, so I use the miles now and earn interest on $ in the bank.

So say I have 5 million miles and $100K.
- I could use the miles now for $200K worth of tickets, or in 20 years from now for $150K worth of tickets.
- I could use the money now for $100K of spending power, or in 20 year from now for $250K worth of spending.

What should I use now?

My lifetime airline plan is lifetime status and lounge access. I already have lifetime AA Saphire status on Oneworld (so alliance wide Oneworld lounge access and double miles), and hope to gain BMI lifetime Star Gold if their program stays around. If BMI doesn't stay around as a desirable program, I may settle for UA lifetime Star Gold (assuming UA is still UA). As for Skyteam, I am contemplating a CO lifetime lounge membership; just trying to figure out how much I will be flying Skyteam though. None of Skyteam programs are as rich as my Oneworld/Star options, so not sure...