I found out the hard way to try out a new kind of thread or spool before buying very much. If the thread doesn't flow properly off the spool while sewing, you need a new kind of thread, spool, or spool holder.
I was reading the manual to my DD's new Babylock, and noticed the recommendation that horizontal spool pins require the crisscross-wound spools and the correct size of spool cap to function properly. It even showed that some types of spools need a small space between the cap and the spool. This is all new to me since I only sew on vintage machines.