Every unit in this country dies of the same thing, and almost nobody washes the part that matters.
In thirteen years of doing this in Malé I have taken apart a few thousand units, and the cause of failure is nearly always the same. Not the compressor, not the board, and not the brand. Salt.
Here is the sequence. The outdoor unit pulls air through a coil of thin aluminium fins to throw heat away. That air carries salt, which settles on the fins and stays there, because nothing washes it off except rain, and rain does not reach the fins of a unit under an overhang. Within a year the crust is thick enough to restrict the airflow. The unit can no longer reject its heat, so the pressure on the high side climbs, the compressor runs longer for less cooling, and the bill rises while the room gets warmer. That is stage one, and it is entirely reversible with a wash.
Stage two is corrosion. Salt holds moisture against aluminium and copper, and where the two metals touch, which is everywhere in a coil, the corrosion accelerates. It eats through the thin wall of a pipe, usually at a bracket or a bend where something has held water against it, and then the system leaks. That is stage three and it is not reversible: a corroded coil is a new coil, which on most domestic units is more than half the price of a new machine.
So the whole story of keeping a unit alive here is washing the outdoor coil. Not the filter, which is easy and which everybody does. The coil, with water and a proper cleaner, from the correct side, which is inside out rather than outside in, because washing it the wrong way drives the crust deeper into the fins. Within two hundred metres of the sea, that is every three months. Further in, twice a year.
Two other things follow from this. Where you put the outdoor unit decides how long it lives, and a unit on a seaward wall will not last as long as the same unit in a courtyard, whatever you do. And a cheap unit that is serviced will outlive an expensive one that is not, by years, which is not what anybody selling units will tell you.
One last thing. If your technician services a unit in twenty minutes and does not have a hose or a pump sprayer with them, they did not wash your outdoor coil. Ask. It is the only part of the job that decides whether you are buying a new unit in year five or year eleven.