Is it worth it? We're talking from discounted economy fares, of course. They cost more (points-wise) than upgrading from full fare economy and you have the pay higher fare disc economy, which is usually 2-3 times the cost of their cheapest economy tickets. Do requests for upgrades usually come through? Is there a priority list depending on the fare class and elite status? I just want to avoid paying a significantly higher fare to be eligible for an upgrade only to be denied it. Thanks in advance.