I have a large stash of vintage and antique thread. Some of it is probably close to 100 years old. I use thread from it regularly in both my needle and bobbin and have no problems as long as it passes the tug test. Also, sometimes the outer layer of thread on a spool will have been weakened by exposure to sun, but if you pull that off, there will be good thread underneath. You may need to lower your top tension some but maybe not. Depends on the thread.
I do not use any of my antique or vintage threads for quilts that will be used as quilts but I do use them extensively in quilts that will be used for wall hangings. I've successfully used the decorative stitches on my machines as well as FMQ'd with them and gotten really nice effects.
Rob