Join Date: May 2003
Location: Redwood City, CA USA (SFO/SJC)
Programs: 1K 2010, 1P in 2011, Plat for 2012,13,14,15 & 2016. Gold in 17 & 18, Plat since
Posts: 8,826
There is no rush to pick up a "standard" award. At least not until you'd have to pay a close-in fee (since you're not an elite on UA).
If you've got miles to burn, you could snag that cheap saver economy fare, and throw it away later (instead of paying to get the miles back) & book a saver biz fare, if it became available. That saver economy fare is what's likely to disappear while you're looking at it.
Unfortunately, you can't simply pay the difference in miles and upgrade to biz from an economy award.
There is one other strategy you could play; find a date that has biz or first saver available that you could make work if you had to, and then try to get the date changed down the road. Only works if that space opens up, and it might not. You've got to watch for it because UA isn't going to tell you.