Soap up pipe on left side. Loosen fitting and slide pipe forward in to tank. You can then remove pump and access all four duckbills. Don't over tighten duckbills on reassembly
I've always just waited. Shower that gets all the use probably lasts 5-6 years. Other sump that is mostly ac drain just got changed after 20 years. Good idea to keep spare since the design change will require a little more work.