Mice can be driven away, eliminating the need for a trap.
I would then add a date, a few notes about the idea and a "next step." Most of these ideas never make it to the next step either, due to lack of time or dependence on a resource that is currently unavailable.
For those that do make it to the next step I would recommend starting a separate journal. This journal should be date stamped and the hypothesis restated as a problem/solution pair.
P. Mice are a problem and traps only provide a temporary and messy solution
S. Create a device that discourage mice from coming on the property
The next step then takes two paths dependent upon your personality type. If you are a solution oriented tinkerer then write down some ways to solve the problem. If the problem appears to have a feasible solution work towards creating a prototype, carefully noting the paths you go down in your journal. This invention chronology can be used later for the patent process. If you are market oriented then answer the following four questions and then go back and pursue the technology feasibility question
- Who does the idea benefit
- How much will they benefit
- How many of these people are there
- Is anyone else providing a solution
Logging all of this data in your journal will help give you the discipline to follow through and encourage the rigor to test your hypothesis.