If you have a set routine on how to pick a club for a shot, you may eliminate both the wood and the hybrid. Start close to your body and work your way out toward the environment and eventually to your target area:
1) How far do you want to hit the ball?
2) What kind of lie? Uphill, downhill, ball above feet, ball below feet, rough, sand?
3) Wind? - club up or down
4) Obstacles? - shape
5) Landing area? - run or stop
To answer your question:
First of all, what's in your bag? 3 wood, 5 wood, 3 hybrid, 2 hybrid?
All these clubs have different distances. I used to have a 2 hybrid and a 3 wood. In order for me to decide to use either, the first thing to consider is "which club for the distance?" If you're on the fairway, you choose the club that will get you the distance. Follow the steps and you may eliminate using a wood at all (deep rough).
The main purpose of the hybrid is to replace the longer irons. Hope that helps a bit. Good luck out there.