Originally Posted by
KL803
and if I don't fly, my miles will expire one year after.
Just to clarify - miles expire 20 months after the last mileage-earning activity.
So while it might be convenient to burn them all in one extravagant F redemption, one Skyteam flight every 18-20 months is all that's really required to keep your miles alive. (And they may come in convenient to you a few years down the road).