The 91-year-old Dunedin resident is among the longest-serving Bank of New Zealand (BNZ) customers, having stayed loyal to the organisation since her first account was opened in 1941.
Mrs Montgomery's cheque book has largely been made redundant by plastic cards, although she gets a helping hand from tellers at the ATM if need be.
It comprises gold-weighing machines, a replica gold bar, Troy weights, teletype machines and more than a century's worth of photographs and information about the bank's changing role, its people and their stories.
This week, it was on display at the BNZ Mosgiel branch, the central Dunedin branch in Moray Pl and the South Dunedin branch. Today and tomorrow, it will be at the Dunedin Home Show in the Lion Foundation Arena at the Edgar Centre.
BNZ opened branches at Mosgiel in February 1875 and South Dunedin in November 1895 - because of demand fuelled by the gold rush.
Mrs Montgomery remembers "feeling great" about having her own bank account at the age of 21.
"I used to go in the bank and even before I got to the counter the boys would have my number out - they had memorised it. I'm still fairly conservative and I like my cheque book but they keep telling me that they'll go out eventually." Dunedin author Gordon Parry is also among the bank's longest-serving customers.
Mr Parry (91) opened his first account with BNZ aged 18. At the time, he was a teachers' college student receiving a wage.
Mr Parry, who moved to Dunedin in 1947, said the old BNZ branch situated in the Exchange was a predominantly male environment.
"In those days, banks were slightly intimidating places and I was quite apprehensive about the place, initially. Of course, there were no women tellers there ... they had a wonderful centrepiece - a desk where people sat to write their cheques," he said.
That "magnificent piece of furniture" was now at the Otago Settlers Museum, Mr Parry said.
A self-confessed "old-fashioned" man, Mr Parry still did his banking in the Moray Pl branch rather than online.
"I go in once a week to collect my pocket money. I must say I find the courtesy is quite remarkable - it's an extremely user-friendly place," he said.
