You may need a carpet cleaner once a year and a drill for twenty minutes. Owning each item means paying for long periods when it does nothing. A tool library makes temporary access available from a common stock, so many households can use equipment that none needs continuously.
The shelves are only part of the institution. Seattle REconomy's lending arrangements include borrowing periods, returns, renewals, and training requirements. These routines turn donated or purchased objects into dependable access.
The return matters as much as the loan
Imagine borrowing a sander for a weekend project. The next borrower has planned their own weekend around receiving it on Monday. Returning it late transfers a problem to someone you may never meet; returning it damaged creates work for volunteers before another loan is possible.
Maintenance, spare parts, storage, and help choosing the right tool are shared costs even when borrowing is inexpensive. A large catalogue can be misleading if popular items are broken or always unavailable.
The library changes the unit of provision from “a tool for every household” to “a usable tool when someone needs one.” That can expand what people are able to repair or build, provided the less glamorous work of keeping the collection functional receives resources too.