Originally Posted by irishguy28

Upgrades can be great if you travel a lot on someone else's expense but you are always booked in economy - the more you travel on such tickets, the greater the chances that, eventually, one of these flights will "co-incide" with available O space allowing you to upgrade.

However, if you are fully in control of booking, then blindly buying any Economy ticket, and then later hoping to upgrade, is a terrible strategy. Once you have selected your flight, you are stuck with that flight - which is already severely limiting your "options" which you need to keep as wide as possible when you are trying to do something like upgrade with miles. People that end up posting here seem to think that they can buy any economy ticket they like, and then upgrade. But as you are seeing, you really need to do your research FIRST. If you buy your economy ticket without even checking/considering whether it can be upgraded before committing to the purchase, then you have already given up all your potential to be flexible as regards choosing a flight which turns out to be upgradable. Far better to use your miles to redeem an award business class seat outright rather than go through the intermediate step of buying an economy ticket and then upgrading.

Or, at the very least, try to find a flight for which you will buy an economy ticket and which is currently available for upgrades, and upgrade it immediately. If the cheap "O" rate is already gone at the time you buy, it is very, very unlikely to become available again at any future date (and, even if it did, would you be "lucky" enough to check at the right time to notice that it did???)