Workflows vs usage limits and "workflow fields"

Does a workflow have usage? It uses standard calls, to my knowledge, so I'm sure it does.

I have very extensive field logic on case records, such as setting various fields mandatory or not, normal or disabled, wiping out their value, all based off a checkbox. In this case, I think only non-usage calls are made, but what if I'm doing Lookups to other records?

The reason I ask is because I can only perform one Action based on a lookup. I have many actions to do so I may have to do many lookups on the same condition each time. In scripting, I can look up a value one time and use it for unlimited actions.