Closures of libraries in Cornwall cannot be ruled out next year, the county's council has said.
The service is under review as the section of Cornwall Council's budget that includes libraries has to make £1.3m of savings.
Some libraries already have reduced opening hours, but none have closed.
Councillor Adam Paynter said he hoped mergers with information points and more cuts in hours would halt the need for closures.
A council spokesman said the number of people using libraries annually had dropped by about 500,000 to under two-and-a-half million over the last two years.
'Never come back'
He said the authority had also been analysing how much each library visit costs the taxpayer, which ranged from 58 pence in Truro to £2.53 in Padstow.
He added that one mobile library service had worked out at £39 a visit.
After a temporary closure, Camelford Library is due to reopen on 3 December as joint library and council one-stop shop.
One-stop shops offer advice and information on all council services. Staff also help people fill in forms and can provide access to more specialist information about services.
Mr Paynter said similar moves across the county could help protect services, but added closures were still possible.
"People have told me that it would be like a primary school - if it closes, if it goes, it will never come back.
"We have to look at if that's what we really want, and we have to look at if there is a better way of working with the budget we have got."