My builds vary, mostly by the complexity of the project.
Some take loads of work, while others take only a few hours of actual work time.
Examples:
The X-wing I'm currently working on might end up with about 15-20 hours of actual work on her.
The BSG-47 Solaria I did for this years BSC was more along the lines of 35-40 hours of actual work because of the modifications for lighting and adding the armor.