As others have mentioned, I do a break test and if it passes and is cotton or polyester it gets used for everything, piecing, quilting, etc. If it passes the break test but is rayon, "art silk", nylon, or unknown content. I use it for decorative stitching on art quilts. I've used very old thread (as in 75 to 100 year old thread) as well as thread from the later half of the 20th century and never had a problem with it in any of my machines (including the PQ1500s and the Sweet Sixteen) as long as it passes the break test and is paired with the correct needle.
Also, some vintage machines are "high speed" if you consider 1500spm to be high speed and some modern machines aren't if you consider 850smp to be slow.
Rob