Design for Assembly is widely used in the automotive, electronics, medical device and transportation industries. For example, skateboards have undergone a design overhaul which has increased both their stability and performance due to better-engineered designs. Many of the changes have focused on increasing the bearing size which reduces maintenance issues associated with smaller bearings working too hard or seizing up altogether.
Another example of DfA would be reducing the number of mating parts by designing the holes symmetrical about an axis. This allows for easier alignment between parts during manufacture as there is no "key" features required to align hole positions across multiple components