"I would say it has gone down from what we used to have."
She said the post office had "just gone with it, just gone with the changes".
Being a postie was not a job she had originally been keen to do long-term but she grew to know the run and really enjoy it, she said.
It was a 7am start and she used to "hurry up and get out there" so she could get home and meet the deadline.
Miss Biddle said she worked at the Rotorua post office for 43 years because she enjoyed her job and her workmates.
She said she knew most of the box-holders and where their boxes were.
"I've got beautiful customers, really awesome customers."
As for the future, she planned to spend some quality time out at the beach for a couple of weeks and then learn the Maori language.
Long-time customer Lee-Ann Mead said she has had a PO box for about 20 years and Miss Biddle had always been the person she went to if she needed help. "I am sad to see her go, but it sounds like she's got some great plans for retirement."
She said the way Miss Biddle was always friendly and smiling had set her apart.
"There's never a time when she's not happy to see you."