Originally Posted by pshuang

Ignore the accumulation of redeemable miles (RDM's) for the moment. If you're flying to LHR every month for the foreseeable future, that's about 8K elite-qualifying miles (EQM's) per non-stop round trip. In 3 such trips within a calendar year (technically, you'd need 3 such trips plus another 1,000 EQM's from some other flying), you'd qualify as Premier on United, which would get you free access to United's Economy Plus seating. On an 8 hour flight, the additional inches of legroom can be quite noticeable for many people. You'd have to decide if you ever felt cramped in economy seating and if legroom would help. Premier also gets you preferential treatment in which check-in lines you can use, how much baggage you can take for free, etc.
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