Aside word from mouth, certain magazines that you'd trust (or unsubscribe otherwise), the most prominent part was: the brand name.
Before moving to Taiwan (and then China) a lot of the goods were produced quite locally and not outsourced, so it was even possible to have a most so remote relationship to the factory/engineers responsible for a product.
The brand is still a thing, yet a lot of brands are owned by the same mega corporation and effectively produced/assembled in the same outsourced factory with unknown amount of suppliers.
Before moving to Taiwan (and then China) a lot of the goods were produced quite locally and not outsourced, so it was even possible to have a most so remote relationship to the factory/engineers responsible for a product.
The brand is still a thing, yet a lot of brands are owned by the same mega corporation and effectively produced/assembled in the same outsourced factory with unknown amount of suppliers.