Seat covers
A cover goes over what is already there. It is quicker, cheaper, and if your seats are sound underneath it can look good and protect them from sun and wear.
The trade-off is fit. Universal covers pull and bag at the edges, and no cover moves with the seat quite the way upholstery does.
A proper retrim
A retrim means the seats come out, the old material comes off, and new panels are cut and stitched to your model's pattern. Perforation and colour are matched to what is already in the cabin, so the result reads as original rather than added.
It costs more, though most retrims still go out the same day — only a full interior in a large vehicle normally stays overnight. It is also the only option that genuinely fixes sun-damaged or split seats rather than hiding them.
The airbag question nobody asks
Most cars have a side airbag in the seat, designed to burst through a specific seam. Upholstery over that seam has to be stitched so it breaks the same way.
This is the one place to be uncompromising. A cover stretched over a side-airbag seam, or a retrim stitched without respecting it, can stop the airbag deploying properly. Ask directly how the fitter handles it.
How each ages here
Abu Dhabi sun is the deciding factor. Cheap vinyl hardens and cracks; a decent leather or quality synthetic with proper backing survives far better.
Whichever you choose, a sunshade and parking out of direct sun does more for the cabin than any product you can buy for it.