Schwarzschild Wormholes
If Schwarzschild wormholes exist in nature they are not likely to be very useful to us as time machines or means of rapid interstellar travel. Firstly, the wormhole would have tidal forces in the throat that are comparable to those at the event horizon of a Schwarzschild black hole. Theses forces would be fatal to us. Secondly the wormhole is not static, it evolves with time. It begins as two disconnected spacetimes with a throat radius of zero. The throat radius then expands to some maximum and the spacetimes meet. The radius then begins to contract and the spacetimes disconnect once again. This expansion and recontraction is so rapid that even traveling at the speed of light would not see us through before we were caught by the crunch of the tidal forces during recontraction, which would certainly annihilate us. Lastly, Schwarzschild wormholes possess anti-event horizons which would be unstable to perturbations just as those in white holes. This would hasten the recontraction phase of the wormhole's evolution making travel through it that much more impossible. So Schwarzschild wormholes are not of any use to us, but there are solutions to the Einstein field equations that are.