That depends, really.
A gubbin is a fool, a small object, a little device or gadget. A whatsamacallit or thingo.
Gubbins are odds and sods, bits and pieces. They may be superfluous, or utterly vital. As usual, context is everything!
HAVING TROUBLE WITH GUBBINS IN YOUR TEXT?
PETER THE PROOFER IS CHEAP AND FAST, NOT CHEAP AND NASTY
A$15 per 1000 words
Particularly good with non-English speakers