Visitors to Grantham Library will only be able to loan a book for three weeks, instead of four, from the start of next month.
The move is aimed at enabling a greater turnover of stock so customers get a wider selection of titles to choose from.
It is part of a drive by charitable social enterprise GLL to improve the library service across the county.
Diana Edmonds, head of libraries for GLL, which runs the Lincolnshire Library Service in partnership with Lincolnshire Country Council, said: “Books are the cornerstone of any library service and since taking over in April we have been working hard looking at how we can improve the quality and selection of stock on offer, ensuring it meets our customers’ interests and needs.
“Moving to a three-week loan period will help us make significant progress towards improving the selection of books our customers have to choose from.”
The change, from October 1, applies to talking books as well as physical books in all Lincolnshire libraries and community hubs.
It is anticipated the move will also reduce waiting time for publications which are not available at a given time.
GLL say improved technology and an emphasis on customer service mean items can now be easily renewed if customers need them for a little longer.
Customer services are available on the telephone from 8am until 6pm Monday to Sunday, including bank holidays, and library users can access their online account at any time if they are unable to visit any of the 15 core libraries or 32 community hubs to renew items.
To ensure customers adjust to the change in loan periods, an eight-week fines amnesty will be held from October 1 to November 26.
Mrs Edmonds added: “I would also hope that the amnesty will be an incentive for lapsed borrowers with overdue items, especially those who are perhaps worried about fines, to be encouraged back into our libraries with the promise of a clean slate and so discover all the stock and activities that are now on offer.”
Items borrowed from mobile libraries in Lincolnshire will retain the four-week loan in line with scheduled stops. DVD hire and loans to subscription groups, Listening Lincs and Home Library Service customers will also remain unchanged.