I wear a waterproof, high-viz jacket on my Brompton commute all year round, so four days per week, 45 weeks per year. I'm on my second yellow Altura Night Vision Evo jacket in three years and it gets washed every week with the full waterproofing lasting for only about 6 months.
I started looking at alternative jackets, some considerably more expensive than the Altura and the waterproofing qualities explained for each are probably comparable to the Night Vision. However, one vendor recommended a regular treatment using their branded re-proofer followed by a tumble dry. I don't own a tumble dryer so I searched for an alternative water re-proofer and found...
You spray it on the jacket after washing and whilst the jacket is still damp, then just leave it to dry.
The weather today was slightly inclement and the rain was beading on my jacket. I am pleased with the result and plan to continue treating the jacket on a regular basis.
I wonder how many hits this blog post will get ;-)