For storage, I have discovered that if you put a little cooking oil in the pump, bump the run button to move the oil around on the impeller it will not freeze up.
I too had a small leak at one time. I put a little #3 Permatex (non-hardening) on the gasket and it stopped the leak. I think pipe dope would work just as well.
I have broke two impellers. The first became stuck from not being used, this was before I started using the oil. I took the pump apart, freed the impeller. After re-assembly (dry impeller), I turned the shaft with screw driver. Turned pretty easy. I then turned the shaft in the opposite direction to see if I could loosen it up more. Big mistake, I broke the impeller. Due to the design, it is easy to damage the impeller if turned backward. I scratched an arrow on the bottom of the pump to show the direction of rotation. I still had not thought of using the oil. The second broke after setting and not being used. The impeller was stuck, I bumped the run button a couple of times, and broke the impeller. After I repaired the pump, I began using the oil. When I turn the pump on, it is obvious the oil works.
I wish you luck on it lasting a few years. I think it will if you put a little oil in it after use, and never turn the pump shaft backwards. A teaspoon is enough oil, more is OK. I prefer cooking oil.
Wayne