Good Day all!

Wondering what your thoughts are regarding which parts may become unavailable soon and would make sense to have on hand in advance of replacement. For example, my car is a 1978 240D 4spd with 136k miles on it. I currently have a clutch slave, front and rear pads, parking break shoes, front inner/outer bearings.

What else would make sense to buy now and have on-hand before things become impossible to get and/or become very expensive.

Thanks to all who reply!