It’s always tempting to do the bare minimum—just touch up that one stain or scratch on the wall. Sometimes that works. But other times, it ends up looking worse.

If your wall paint is still relatively new, and you have some leftover paint from the same batch, small touch-ups in less visible areas can blend in well.

However, if the paint is a few years old, chances are it has faded slightly. New paint from even the same shade code can look fresher and create obvious patches, especially on large, plain walls.

If there’s been water damage, mould or a major repair, it’s almost always better to treat the problem, prime the area properly, and repaint at least the whole wall if not the entire room. Otherwise, the fixed area will stand out.

Rooms that see a lot of wear—kids’ rooms, hallways, near switches—might benefit more from a full repaint after some years rather than constant little patches.

A good rule: if more than 20–30% of a wall needs touching up, it’s probably time to repaint it fully instead.