"Spot the differences"
Solitaire is the highest tier in Singapore Airlines' frequent flier programme. Its perks are incredibly popular. I know people who normally fly Economy (which doesn't contribute towards Solitaire qualification - you have to fly Business or First) but throughout the year carefully spend the extra money on a few Business Class flights in order to stay Solitaire. Perks are things like priority seat reservations and luggage handling, access to SIA's First Class lounges all over the world, and the prized First Class check in at Changi Airport (the Ritz Carlton among check ins).
So Singapore Airlines are a textbook example of perfect loyalty managers? Not always. In 2008, for inexplicable reasons, Singapore Airlines removed the number of membership years which until then had adorned each card. It's the easiest thing to do, and it doesn't cost the company a dime. Credit card companies have known this for a long time. It reminds people time and again of the period they've been valued customers, and it provides a subtle but continuous incentive to stay that way and increase the little magic number.
I just received my new Solitaire card, and I was pleased to see that SIA 1) hasn't thrown away the precious information of their top tier customers' seniority and 2) has put it back where it belongs - on the card.
If you want to increase customer loyalty you don't always need to throw money at it. Common sense helps too.