In addition to lots of good comments you have already received, I'll add a couple notes.
Some old tools were designed to let you do some inherently unsafe things. Radial arm saws are one thing that comes to mind. They were designed to be a one stop shop, but really compromised safety to do that. If you have one, do some reading or watch some videos of modern woodworkers on what you can actually safely do with them.
Another thing to look out for is that old tools can sometimes have a lot of vibration. As things get older, bearings wear down, and screws/bolts can loosen. If you notice a lot of vibration, you can go around the tool to try and find anything loose. Many tools have a lot of adjustment points to ensure things are well balanced. If you are really handy, you can also replace bearings. Another trick I used with an old contractor saw was placing weights on the shelf under the body of the saw. Generally, more mass is less vibration; that's why cabinet saws weigh so much.
Really, if I were you, I would just post pictures of what you have to this community. That's a good way to get more specific advice.