You just have to wash the item with the proper stuff to make sure it stays waterproof/breathable

The Rohan jacket and trousers in whatever the waterproof/breathable material is that they use, says it needs no proofing. It has remained waterproof through normal washing for five/six years. I've had no such luck with waterproof walking boots, which seem to lose the effect in two to three years.

The appalling, unruly Boxers: Baskerville, Buddy and Holly have appallingly expensive Barbour dog coats ( I just pay the plastic) which need to be properly proofed, each time!