There are fixed costs and variable costs and the total percentage will drop the more volume you do. I expect to do about $20,000 more than last year but my expenses will be about the same as last year. So many things vary.
I made my coverage area smaller this summer going from two counties to basically one county except for certain assignments. It costs a lot of $$ to drive an F-150 80 miles round trip for a SFR assignment. I have more private work that pays better and consolidate those assignments for less driving. With a month or two turn time I can visit the insurance house on my way to a lending assignment.
Different appraisers doing similar work could have vastly different expenses depending on location.
Fixed costs:
E and O: $1,000 ($3mm coverage)
MLS: $1,800
Data Sources: $4,000 (can vary)
AI dues: $1,500
Software: $600
Cell Phone: $3,000
Internet/office phone: $2,400
Variable costs:
Auto expense $10,000 (I don't deduct mileage but actual auto expenses and every five years buy a new truck that I write off entirely.)
Computer expenses (ink, maintenance, etc, and replace every five years)
FICA taxes
So above I have about $25,000 in expenses and I left some off. An appraiser grossing $100,000 will have 25% +/- in expenses but the appraiser grossing $150,000 will have 17%. One also has to consider a specific person's situation. I don't have to pay for health insurance as we get it through the hospital my wife works at. Some appraisers have reported health insurance as being as much as $2,000/month.