Started with 2- a very old Riccar serger, and my beloved Pfaff 1475.
Now- 5- new serger (still have the old awaiting repair) replaced the 1475 with a QE 4.2 (it was an upgrade, but NOT an improvement!) and added a Featherweight and a treadle. My daughter got the 1475- it still works but can no longer handle higher speeds. And I'm constantly eyeing older mechanical machines and awaiting a chance to buy a Viking similar to one I had decades ago.