Should I buy a book or borrow it?
Borrow by default from the library and buy only the books you'll reference repeatedly, mark up, or want to keep — most books are read once, which is exactly what borrowing is for.
beginner
Since most books are read once, borrowing is the low-cost default and saves shelf space. Buying earns its place for reference works, favourites, and books you'll actively annotate.
What it is
Verdict: Borrow first. Libraries — physical and digital — cover the vast majority of reading at no cost, and most books are read once and never reopened. Buy the exceptions: books you'll return to, mark up, or genuinely want to own.
It depends on: whether you'll re-read or reference it; if you like to annotate; how long the library hold queue is; whether you want it permanently; and your shelf space.
How to decide: (1) Check the library first, including its e-book and audiobook apps. (2) If you only need it once and can wait for a hold, borrow. (3) Buy reference books, textbooks, and favourites you'll revisit. (4) Consider second-hand or e-book for buys to cut cost and clutter. (5) For a book you're unsure about, borrow it first — then buy only if you find yourself wanting to keep it.
Pitfalls: buying books that end up unread on a shelf (the pile of good intentions); and buying new when a library copy or used edition would do. Sampling by borrowing first prevents most regret purchases.
Worked example
A novel you'll read once is a perfect library borrow. A cookbook or professional reference you'll open dozens of times a year genuinely earns a spot on your shelf — that's where buying pays off.
Failure mode — when it misleads
The familiar mistake is buying books faster than you read them, building an expensive unread pile, when borrowing first would have revealed which ones you'd actually finish and want.
How to apply it
Ask: (1) Is it in the library, print or digital? (2) Will I re-read or annotate it? (3) Do I want to own it? Read-once, borrow. Reference or favourite, buy — used or e-book to save.