Right. Even George Daniels bought mainsprings and hairsprings (along with sapphire crystals and dial engraving, probably rose engine work?) for his 25 handmade watches.

> In total he (George Daniels) created 25 handmade watches which were completely made by himself (23 pocket watches and 2 wristwatches) other than the crystal, the mainspring, the engraving of the dials and the hairspring. One pocket watch remains incomplete and is not included in this total number of pocket watches produced by George Daniels.

https://en.m.wikipedia.org/wiki/George_Daniels_(watchmaker)