The biggest clogger of septics is the polyester fibers from your washing machine. They do not break down. Put a secondary filter on the washer line and check it every 2-3 months.
My neighbor septic system clogged up, he eventually found out the problem, the grandchildren were stealing the candy and flushing the wrappers down the toilet.
You are correct. Another solution is to valve the washer drain to a grey water tank or system and bypass the septic.