In expensive metro areas, sticking rigidly to 30% can mean an unrealistic commute or living arrangement, while in smaller cities with lower rents, spending well under 30% is often easily achievable without much sacrifice. A more useful approach is to think about rent as one part of a broader housing cost picture — commute time and cost, proximity to work, and how much the location affects other spending (eating out more because you're far from home-cooked options, for instance).
It's also worth weighing rent against your other financial commitments rather than treating 30% as a standalone target — someone with significant loan EMIs or dependents to support may need to keep rent well below 30% to keep their overall budget sustainable, while someone with no other major obligations might reasonably stretch further for a location that saves substantial commute time.
Rather than chasing a fixed percentage, calculating what's left over after rent, essential expenses, and savings goals — and checking whether that remainder is genuinely comfortable — tends to be a more honest test than the percentage rule alone.