Answering a couple of points made earlier.
The number of Audible credits you can hold over depends on the kind of membership you have. You can freeze your membership more than once a year but can only do it yourself online one a year. If you want to freeze more than once you have to do it through customer services by phone or webchat. Generally, they expect you to buy at least one credit betwen freeze periods.
As for Audible v “free” library audio books, which we pay for through our taxes, it really depends on what you like to listen to. For example, when the 2021 Booker shortlist was announced in September 2021, Audible already had all six titles. Borrowbox had none. By January 2021, Borrowbox still only has two of the six and neither is the book that won. The same often goes for other major prizes. Libraries are constrained by their budgets and whoever is making the buying decisions for paper and audio books. If you want to read or listen to a book as soon as it is published, the library isn’t the best option.
If you buy an annual subscription, that works out at less than £6 a book, less than you will pay for a new book especially one that isn’t yet out in paperback.
I have a habit of equating the cost of things to cups of café coffee. A flat white in the high street chains is now over £3 and is gone in ten minutes. By comparision, listening to 30 hours of a big novel for less than £6 represents excellent value for money.
It really does depend on reading and listening tastes and habits. I like paper books and audio books. I was gifted a Kindle and gave it a good workout but didn’t enjoy using it. Not all books on Kindle are inexpensive. Take Damon Galgut’s 2021 Booker Prize winning The Promise as a example. It isn’t out in paperback yet. The hardcover book costs £16.99 in Waterstones and Hatchards or £8.00 on Amazon. A standard monthly Audible credit is £7.99. The Kindle version is £9.99. My county library doesn’t have it in book form either yet.