Dubai Hills villa still looks newish but the walls are scuffing and marking, repaint everything or just touch up?

The honest answer on a house this new is that it is almost never the paint failing, it is the grade of finish the developer used, a flat budget emulsion that marks the moment anything touches it and then goes shiny where you spot-clean, which is exactly what you are describing. So the decision is less repaint-versus-touch-up and more this: if the marks genuinely will not wash off, the sheen has gone patchy from cleaning, or you are about to re-rent or sell, a full repaint of the high-traffic areas is worth it; if it is a few isolated marks, neat touch-ups in the exact same paint and sheen are fine and far cheaper. The upgrade that actually stops you being back here in a year is the finish itself: moving the busy areas (hallways, stairwells, kids' rooms, kitchen) to a proper washable or scrubbable paint over sound prep, so a wipe lifts the mark instead of polishing a patch. On a modern Emaar home you also want the colour and batch recorded so future touch-ups match. A painting team that knows Dubai Hills and these newer villas will tell you honestly which walls need a full coat versus a touch-up, and spec a washable finish for the rooms that take the punishment. Spending on the finish grade, not just the labour, is what buys you the quiet few years.