Every square inch deserves a job. It does not follow that every square inch deserves a cupboard door. An awkward corner can consume a surprising amount of attention for somewhere you keep one roasting tray.
Compare two complete cabinet runs
Ask for both layouts at the same scale. In the first, show the corner fitting fully open. In the second, close the corner and draw the drawers or cupboards that become possible beside it. Compare the whole run, including fillers and handle clashes.
If the empty corner only produces another narrow cupboard, it may be a poor trade. On an L-shaped kitchen, closing the corner let us widen the drawer bank beside the cooker enough for the everyday pans. We marked out both cabinet runs with their fillers and handles. The mechanism version held more on paper but made the useful drawer awkwardly narrow. That was the space the owner reached for every evening.
Put the casserole dish in the demonstration
Try the real shape of what you intend to store. Bring the casserole dish with its handles and the roasting tray with its rack. For that kitchen, we still tested a corner fitting before ruling it out: the tray had to be tilted through the opening, then turned again to sit down. It could be stored there, but retrieving it was a small furniture-moving exercise. Don't pay for a clever movement until you've tried it with something inconvenient.
Blum’s corner application information includes purpose-made corner storage. IKEA’s pantry planning examples also show rotating corner trays. Compare the exact fitting drawings rather than assuming any mechanism fits an existing cabinet.
Give the corner an honest job
Choose a mechanism when it stores things you can comfortably retrieve and the neighbouring cabinets still work. Choose the unused corner when it creates demonstrably better access elsewhere. The kitchen does not need a perfect storage percentage. It needs somewhere sensible to put dinner’s pan.