Similar to Tony’s comment (btw Tony, we have an opening for a Project Manger in our Imperial Guard division), is that resources are booked on other projects. So a tool that is aware of the same resource on multiple projects, so that you can’t book a person when they’re already schedule on another project… as well as if they’re 50% on one project, that they can only be scheduled for the remaining 50%.

And to expand on Tony’s idea, being able to plug in how many hours we have of a resource. E.g some resources we have do 60hrs/week, and some are 45.

In MS Project I seem to spend heaps of time ‘massaging’ the schedule into a realistic shape because MS Project doesn’t seem to know that one developer can’t devote 100% of their time to two tasks at the same time.