Even experienced ppl catch the gut once in a while..
Also you may find a gut hooked fish will contaminate your board as well.
Those who fillet 'commercial' style, quick straight cut behind skull, one slice down, get away with it.. and waste a lot of meat. In the commercial industry most of this is recovered for reconstituted products.
Fillting rec style with respect, to recover as much as possible, clipping the gut is very easy to do..
Rule of thumb to know if you are recovering as much as possible, the fillets will weight at least over 1/3 of the total weight of the wet fish
We do the later, hence why we have gutted at sea for several yrs now. Little bit more work on the boat, far less work cleaning down bins , filleting benches boards, and fish dont lay in crap in the bin.
Also results in a significant difference in the meat..as it chills lot faster in the bin, and cleaner.
Always rinse salt water fish/ fillets with sea water. We bring home around 5L with us.