The replacement vanity fits the wall measurement exactly. Then the bathroom door opens into the handle, and the bottom drawer cannot be pulled out fully. Width was checked; movement was not.
Draw the moving parts
Measure the existing room carefully, including the door swing, skirting, plumbing positions and other fixed features. Use the manufacturer’s full dimensions, not only the cabinet’s nominal width. Handles, worktop overhangs and drawers can extend beyond the main box.
Mark a proposed footprint with a removable method suitable for the floor. Use a cardboard template where helpful. Open the room door and any nearby storage, then imagine a person standing where the drawer or basin will be used.
Try the ordinary sequence
Walk into the room, close the door, reach the basin and access the storage. Check whether two actions conflict: a drawer opened while the room door moves, or a person reaching a towel while another uses the basin.
Do not assume that reversing a door or moving plumbing is a small adjustment. Ask the relevant installer to assess feasibility, local requirements and the effect on access, waterproofing and services before ordering.
Separate a comfortable layout from a compliant one
A paper mock-up can reveal obvious conflicts, but it cannot establish structural, electrical, plumbing or accessibility compliance. Use qualified advice for the work and the rules applicable to the property.
If the room needs to accommodate a particular mobility aid or assistance arrangement, test the intended use with the person concerned and suitable professional guidance. A generic clearance found online may not meet their needs.
Record the chosen product’s exact model and drawing revision with the agreed measurements. Ask the installer to confirm the final layout before the purchase becomes difficult to change.
A smaller cabinet with usable drawers may serve the room better than a larger one whose storage remains trapped behind a door. The right fit includes the space the furniture occupies while it is being used, not just the outline it leaves when everything is closed.