Happened to me about 6 years ago. A bunch of trips over a short period of time, with my membership year coming in the middle of the trips, meant that I qualified for silver and then almost immediately re-qualified for the next year. Then my circumstances changed (2nd kid, new job, cheaper flights on other airlines, etc.) and I think I only used my silver card once or twice over the next 21 months... and that would have been on LHR-PRG flights. What a waste... I know better now.