I have found that the tiny gum screws that tighten the tonearm base also work loose, I unscrew them to allow VTA adjustment but have found over time they loosen and you can hear it as it affects the tonearm integrity substantially.
Also found my cartridge moves in the headshell very slightly over a month or so and therefore have to realign for overhang, probably caused by vibration and mechanical interaction of cartridge with record surface?
Main system : VPI Scout 1.1 / JMW 9T / 2M Black / Croft 25R+ / Croft 7 / Heco Celan GT 702
Second System : Goldring Lenco GL75 / AT95EX / Pioneer SX590 / Spendor SP2