Let me put my 2¢ in here.
I have been told all sorts of stories about selenium toner and, to hear some people tell it, the stuff is like weapons grade plutonium.
Yes, I agree! Selenium is toxic but it is not nuclear waste! If you handle it carefully as you would any other chemical, you will be just fine.
Wear gloves. Wear goggles. Wear an apron. Make sure you have adequate ventilation. Use all the safe practices that, if you are good photographer, you SHOULD already be using.
People use paint thinners and chemicals in their houses every day without a second thought. You sit in your car, sometimes, just two feet away from a tank full of flammable gasoline. Nobody worries about stuff like this in the least but I actually had one guy tell me that a "friend of a friend" got cancer from selenium toner because a few drops of it spilled on the floor. This guy truly believed that!
If you spill some toner, mop it up with plenty of detergent and water then put the dirty mops and utensils in a plastic bag, tie it up well and put it in the trash. If you spill more than a little bit of it, you would be wise to take the soiled materials to your local Haz-Mat Amnesty site.
For cryin' out loud! People shouldn't make this a huge issue.
*** Now, back to Planet Earth! ***
Jeff, I think you are right. You would be wise to put your toner into newer, more reliable containers. As long as they are full, unused and/or have not been opened they should not go bad for the foreseeable future. If stored in a cool place, in a good container there should be no problems as long as you want to keep the stuff.
You probably do have a lifetime supply!
It is my practice to keep my eggs in more than one basket. I would not combine smaller bottles into one large one. If one container spills or breaks you have less problems to worry about. If you use with smaller amounts of solution at one time, there is less chance of contamination or other screw-ups spoiling all of your stock. Should there be an accident, smaller amounts of chemicals are easier to segregate than large ones. (Assuming we're not talking about "industrial quantities.") If stored in smaller, airtight bottles, you will have fewer concerns about your stocks going bad due to oxidization and spoilage.
I think you are on the right track. Your common sense seems to be serving you well.