McCartney told Hosking that touring concerts had changed enormously since the pre-Beatles days as the Quarrymen, when he and John Lennon played through a shared amp.
"From when we started out it's a completely different thing. We started in a van."
In particular sound systems were now much more advanced than the baseball public address system the Beatles used at Shea Stadium in 1966.
"We couldn't get heard above the screaming girls."
The Beatles legend performs at Mt Smart Stadium in Auckland on Saturday night.
He's determined that the crowd gets their money's worth and the current shows can last up to three hours. Hosking noted McCartney had enough material to perform for nine hours.
"That would be a bit knackering," McCartney noted.
He agreed that continuing to perform live helped keep him young at the age of 75.
"I do it because I like it and I think there is that thing where you give up what you're used to doing you can a bit sitting by the telly all day and I don't fancy that," he said.
"People pay big money to come to a show so I feel obliged to give them a good time."
McCartney said he tried to select a song list that he would want to hear if he was a fan – and he acknowledged that the older fans wanted to hear Beatles material – but said younger fans knew his more recent work better.
"I do love it and I do it because it's great fun."
