[AZKen]

To answer completely this time:
1. You don't use it very much, so it's not "wearing out".
2. There is no way to know if one is better than the other. They are all made in the same Chinese factory.
3. I would have to know, how you know, the pumps are failing.
4. If it is failing, it's possibly because the diaphragm is drying out or your environment there is causing deterioration to it. Maybe too much moisture instead of drying out. Some kind of damage/blockage due to condensation.
5. If you don't start it much, all the fuel in the carb and in the pump will dry out. The procedure for infrequent starts is to put fuel down carb throat to help truck start for 5 seconds at a time, and save long cranking of starter to get fuel up to carb thru pump. What is your procedure and what happens? Won't even fire once? Won't stay running? Sputter/backfire? Runs rough? You may want to put Sta-Bil in your gas tank, which needs to be circulated into all the of fuel system before shutdown.
6. Funny things happen and make us think it's one thing when it's another. Example: A person thinks his motor won't start because of the fuel pump, but does not test properly. Buys a new fuel pump and filter. Then it starts. But the problem was the filter....... but it's never discovered.
7. What motor do you have and what is the Napa part number of your pump?