Sewage pump needs frequent priming?

I've recently been having problems with my sewage pump running continuously but not removing water from the basement, eventually causing flooding. The first thing I notice when it does this is that the basement toilet starts to overflow, and then the water in the reservoir hole rises and eventually water starts seeping through the basement floors.

I had my uncle come and look at it when I was having one of these emergencies and he taught me how to check the pump and prime it; however I had to prime it a few days ago as well when the basement started flooding and I am worried that the pump may start acting up again soon.

Is there anything I can do myself to prevent the pump from drying out, or should I replace the entire thing?