It's only one type of spell casting that suggests one should let go and forget about the spell completely. There are other ways; ones that involve going to it for a certain amount of time and working it again.
The idea behind it is that constant ritual makes the working more powerful, you are giving it your time and dedication, feeding the work. If one worked with spirits for this goal, it would show care and dedication for the cause. It could also be a time to give offerings in hopes of winning favor. Another way to look at it is that you are actively working the spell during the ritual, so repeating the process is continuing to work it spiritually.
Personal preference should preside on this. And I agree, if one were to think negatively about the spell and the results, it would be detrimental to the process. Either way should be fine provided the person is working towards possible goals.