A compact hatchback and a large SUV do not need the same lighting plan. Cabin size changes the distance between power points, the length of suitable trim routes and how much illuminated area feels balanced.
Small cars
Compact interiors often need less strip length. Shorter runs can be easier to keep tidy, and strong lighting can feel brighter because surfaces are closer together.
Larger cars
A larger cabin may need longer routes or more than one lighting zone to create an even effect. That does not mean choosing the longest product automatically; measure the actual path you plan to use.
Measure the route, not the vehicle class
Two cars in the same category can have very different dashboards, consoles and seat layouts. Use a flexible tape measure along the intended route and include the distance to a suitable power point.
Keep safety zones clear
Whatever the vehicle size, keep lights and cables away from pedals, steering components, airbags, moving seats, vents and essential controls.
For a practical measuring method, read How to Measure Your Car Interior Before Buying LED Strip Lights.