I believe that pricing should be based on the workload and not a fixed contract we both know might be changed along the way. This way it doesn't matter if you need help with something quick or have a bigger project. Repeat customers will receive discounts and/or priviledges as a token of my appreciation. It is also possible to structure another billing-structure on larger project(s).
* Billable minutes are those spend actively on the project or researching project-specific knowledge. It does not include customer consultation/interaction.