How would you prepare and paint an exterior galvanized garbage can to avoid peeling, as it is exposed to freezing and harsh winters?

Which interior wood finish is best to use, to keep the wood trim looking white longer, oil based or water based?

I did some patch work on our bedroom walls prior to painting; then used Kilz interior acrylic (not oil based) to prime those spots. I didn’t read the fine print good enough….and I have now painted two coats of paint (with primer) on walls, and all the Kilz spots continue