Second-hand puzzle listings are everywhere, mostly 1000 piece ones, and nearly always from people who love puzzles as much as we do: they did them, broke them up, and want the box to have another life. If you buy used jigsaw puzzles, you are usually dealing with honest sellers. Even so, a second-hand puzzle carries risks that have nothing to do with the seller's good intentions, and it is worth knowing them before you decide.

We are a shop that sells new puzzles, so we read this through that lens. We have tried to be fair.

What can go wrong with a used puzzle

The best known risk is a missing piece. Sellers rarely count a thousand pieces before listing, and it is not dishonesty: counting a 1000 piece puzzle takes longer than you think, and almost nobody does it. A piece may have ended up under the sofa, stuck to a shoe, in the vacuum cleaner. In a 48 piece children's puzzle you spot a gap straight away. In a 1000 you only find out at the end, with the hole staring at you from the middle of the sky.

Next comes mixed pieces. In homes where lots of puzzles get done, a piece from one sometimes ends up in another's box. Usually it is one or two, but that is enough to confuse you while sorting by colour.

Then there is the box that does not match what is inside. It happens when the original box got damaged and the pieces moved to another, or when two puzzles of the same brand and size swapped boxes. Without the right picture in front of you, a 1000 gets a lot harder.

After that, the state of the board. A puzzle done several times loses its firmness: the tips lift, the printed layer peels at the corners, the fit gets loose. If it was kept in a shed or a garage, damp warps the pieces and leaves a smell. Sun from a window fades the colours, and colours are the clues you need to separate areas.

There may be traces of glue. Someone who glued a finished puzzle and later changed their mind sometimes breaks it up again, and those pieces never fit properly afterwards.

Finally, returns. In a private sale, there is usually no exchange or refund. If a piece is missing, the conversation tends to end with an apology.

If you are buying a used puzzle, ask this

• Was the puzzle completed? If so, whoever did it knows whether a piece was missing. This is the most useful question of all.
• Was it counted after being broken up? If yes, great; if the answer is "I think it is complete", read it as "I do not know".
• Where was it stored? A shelf indoors is not the same as a basement.
• Are there smokers or pets in the house? Board soaks up smells and hair.
• Can you send a photo of the pieces out of the box? It shows the state of the board and whether any pieces have a different finish.
• Is it the original box? Check that the name, brand and piece count match the listing.

If the seller answers all of that without hesitation, you already know a lot.

When a used puzzle makes sense

There are cases where a used puzzle really is the best option, and there is no point pretending otherwise.

The first is a puzzle that is no longer made. If you are after an old, discontinued image, second-hand may be the only way. A missing piece is then a risk you take with your eyes open.

The second is swapping with friends or family. When you know who did the puzzle and how it was kept, most of the risks disappear. Some neighbourhoods and libraries organise swaps like this.

The third is when a missing piece will not keep you awake at night. Some people do puzzles for the process, not the result: they break it up at the end and never think of it again. For them, one piece short is a detail.

And there are used puzzles that are actually new: given as presents and never opened, still in the wrapping. The only risk with those is that the box may have picked up damp.

When it pays to buy new

For a gift, nearly always. A puzzle given as a present should arrive sealed, with the image you chose, and the person receiving it should not have to count pieces. In our shop you can also add gift wrapping for €2 on the product page.

For children, too. Pieces that have been through other hands and other homes, in a puzzle little ones will put in their mouths or spread across the floor, need at least a good clean, and board does not like water. Goula's wooden inset puzzles for the youngest, or Educa's Forest progressive puzzles, with four puzzles of 12 to 25 pieces, are the kind of box worth starting fresh. There is more in our puzzles for children.

And for difficult images, even more so. In a sky, a sea or a field of a single colour, one missing or warped piece ruins hours of work. Educa's Jellyfish, with its dark sea background, is exactly the puzzle you do not want to see incomplete.

What you get with a sealed box

In a new box, every piece is there, the picture on the box is the puzzle inside and the board has never been bent. In our shop, every product page shows the piece count, finished size, difficulty and estimated time, and you pick the exact image, with no surprises. If you change your mind, you have 14 days from delivery to return it, unopened and in its original condition (the return cost is yours).

A few examples that show what choosing the image means. Olivo's Pena Palace has its yellow and red towers set against a sunset sky. Rabelo Boat, from the same range, shows Porto's riverside reflected in the Douro. Clementoni's Disney Classics brings together characters from several generations. And Sushi Kawaii is a sushi bar full of little dishes with smiling faces, every one different.

The rest are in our adult puzzles, all new and sealed.

And if you have puzzles at home you will not do again, pass them on to someone you know, with a note saying whether they are complete and where they were kept.