Spiffy studio trick o' the day:
If you're like me, you can't afford to buy solid gold mic stands with gyroscopic balance circuitry, and you've had your fair share of valuable mics come crashing to the floor when you have the boom extended. Take out a $6 insurance policy: buy a 10 pound barbell weight and slip it onto the bottom of the mic stand:
Notice how it's at full height, the boom arm is fully extended, there's a heavy mic on it, and the arm is pointing out between two of the legs (the least stable position). It wasn't going anywhere. Neat.