I used one for a farm that is 30 miles from home.  It is reassuring to have a second set of eyes on the field at least one a week and helps me feel less need to go drive around it every few days, except for when we are irrigating.  He is an independent, well educated and very professional.  They are not cheap to have around but I really appreciate his opinions and suggestions.  I also use a Servi-tech consultant for some seed corn fields close to home, mostly because the seed company encourages it, plus we are kind of new to the process and appreciate his advice.