Don't burn the balsamic!

I've seen a lot of chefs put a pot of balsamic vinegar on the stove to make a reduction, only to get suddenly very busy, forgetting the vinegar until it's a burnt mass of goop in the bottom of the pot.
This gets to be very expensive, so I urge the use of a double boiler for making the reduction. It takes longer to reduce, but you can still be busy doing other things, just so long as you are checking the water level in the bottom pot every so often; don't let the simmering water touch the top pot, and don't let the water evaporate.
I just keep it in squeeze bottles in the fridge for ease of use. If it thickens, just microwave for a few seconds, or put the squeeze bottle into some hot tap water for a few minutes.