A few words on replacing your humble porcelain throne

S-trap, P-trap, back-to-wall, close-coupled, wall-hung, link suite, plastic or vitreous china cisterns with back, bottom or top inlets... Searching for the right humble toilet suite can quickly become a ceramic nightmare.

If you're doing a full bathroom renovation and can move the water inlet and waste outlet around, the world is your oyster, you can pretty much install whatever toilet suite catches your eye.

Replacing an existing toilet is a different story.

Whether your old lavatory is stained, cracked, leaking, or simply giving off bad vibes, your choice of replacement is often limited by the location of the existing water inlet and waste outlet. If they don't line up with your new toilet, it simply won't fit.

Before buying a new dunny, there are two crucial measurements to check:

Waste outlet

• For an S-trap, measure from the finished wall to the centre of the waste outlet.

• For a P-trap, measure from the finished floor to the centre of the waste outlet.

Water inlet

• Measure the height from the floor and its distance from the centre of the waste outlet. This determines whether the new cistern will connect without altering the pipework.

Another important consideration is the footprint of your existing pan. (The pan is the plumbing term for the part you actually sit on.)

If the existing pan has been fixed down with silicone, you're in luck. If it's been cemented to the tiles, removing it can crack or lift the tiles. Even if the tiles survive, the old cement can leave permanent staining. If your new toilet has a smaller footprint than the old one, those marks may remain visible, especially if Granny's secret tile-cleaning recipe and a generous amount of elbow grease don't quite do the trick.

Replacing a toilet might look simple, but there are plenty of little details that can turn a straightforward swap into an expensive headache.

As always, we recommend having a fully licensed and insured plumber inspect the job and discuss your options before you send your overachieving hubby to Bunnings wearing nothing but a tool belt.

Awkward.