So far, more than 3,500 have been assessed and as a result more homes removed from the list and others added.
Historian John McCormack said planners must be "flexible" with owners with regards what warranted listing.
Last year he labelled the planning backlog for protected or listed buildings as "outrageous".
Mr McCormack said: "I'm whole heartedly behind the listing idea but that doesn't mean everything inside is worthy of listing.
"You've got to do it with humanity, courtesy and flexibility and you have to say to people why you want their home to be listed and get their interest going.
"They will be the best preservers of what is inside, they after all live there and it's their homes, and they want them to be the best as possible."
In 2012 Guernsey's Environment Department held a questionnaire asking how important it was to protect Guernsey's historic buildings.
The results showed a majority felt it was important but views were divided on the buildings that should qualify.
The States of Guernsey planning department has said it is making "steady progress" on visiting and classifying listed buildings.