I got tired of mixing up a whole gallon at a time and having it go stale. Then I used it anyway, and it would eventually gum up my carburetors.
I'm currently using Castrol (or maybe it's Penzoil) 100:1 rated TC oil in a quart bottle. When that runs out, I may switch to QuickSilver PWC (from Mercury Marine) synthetic oil -- the TC stuff, not TC-W3.
Now if I could just come up with a good method of remembering when I last filled all my gas cans, so I know how old the gasoline is. (do you think a blackboard in the garage would work?) I use Stabil in the 6-gallon cans for the generator, and dump them in the truck and refill about twice a year. It's the little cans that I can't keep track of.
BTW, I buy one 2-gallon can of 91+ octane Premium gasoline in the spring for the first tank or two of gas in the mower and tiller (etc.) They seem to start easier that way. When that can is empty, I switch to Regular for the rest of the season. By then they are either running good, or they are not going to run good 'til I get them tuned-up. ;)