Originally Posted by
Unterwegs
Miles and More has no expiry as long as you hold their co branded credit card (at least in the US and Germany)
That is not exactly right. For the US card, you
must make a charge on the card every month. If you miss a single month, your LH miles will expire.
DL is the only major program I know of where your miles don't expire.
Though it is pretty easy to keep UA miles alive. Including by having a co-branded Chase card (without the ridiculous monthly purchase requirement that LH requires).