The number one thing the OP can do to reduce rim wear is move. It's nearly impossible to wear through a rim on the road under normal riding conditions, but commuting in Portlands wet weather means the shoes will constantly pick up rod grit and be unusually abrasive.

OTOH- I believe the rim wear issue is overblown, possible even for Portland commuters. It takes a long while to wear the brake track to where failure is a real possibility. This isn't to say it's impossible, just that it's a long slow process, and most wheels die accidental deaths beforehand.

The strength needs are proportional to tire width and pressure, so if riding with narrow tires at 100psi, you can let the rim wear more than someone riding wider tires at similar pressures. IME- you can wear away roughly 1/2 the original section at the thinnest place, so if concerned, use a dental caliper or improvised gauge to measure a new rim (of th same kind) and yours and see how you're actually doing.

Or ride until you feel the pulsing that's indicative of the rim bowing out under pressure stress. When riding a rim, I'm not sure about I over-inflate 15-20% then bleed back to riding pressure. This gives me a pressure test at higher stress and ensures a safety margin when riding.