Try both complete arrangements
Draw the closed and extended table outlines. Add the seating positions and the route to the kitchen in each case. The small arrangement may work perfectly while the larger one leaves a cupboard door hidden behind a chair. That may be acceptable during an occasional meal, but it is better to know before buying.
Consider how the table moves as it opens. Some extend at one end, while others separate in the middle. If you want the centre to remain under a pendant light, these mechanisms are not equally convenient. Check the actual construction in a showroom or its instructions instead of assuming how it works from a photograph.
Make the changeover realistic
Ask to see the whole opening procedure. Does it involve lifting a heavy leaf? Is a second person required? Where are the releases, and can you reach them with the table in its intended position? A demonstration in a spacious showroom may conceal the extra movement needed in a small dining room.
Check that the extension sits level and consider where the legs end up. On some designs, their position changes as the table opens. An additional place is therefore not necessarily as comfortable as the original seats. Try the chairs in the extended arrangement with the same care as in the everyday one, including knee space beneath the joins.
Find a home for the spare parts
Leaves stored inside the table remove the need for a separate storage spot. Loose leaves need a dry, protected location where they can be stored in the position specified by the maker. Decide where that will be before ordering. A leaf squeezed behind a tall cupboard may be out of sight but too awkward to retrieve regularly.
Spare chairs need to be accessible too. A table that extends easily is less useful if reaching the folding chairs means emptying several storage boxes. Decide which objects will move when visitors come: perhaps a small side table, rather than an entire bookcase. Planning this short changeover is what turns the extension into something you will actually use instead of a feature that feels too troublesome on the day.
