Consulting Appraisers before purchase

[William Leonard]

Very unseasoned investor, please excuse me if this is a dumb question. 

Is it normal to consult with appraisers during the pre-purchase/researching a property phase?  Outside of getting a full appraisal done beforehand, are there simple calculations that can be done early on in the process. 

Obviously I'm running comps myself and getting CMA's from my Real Estate Agent, but coming from a Finance background I like having as much data available to me.