For me, some things make better sense in metric and some in US customary (USC) measurements.
For fasteners, I'd rather work in metric, but typically you don't get the choice. It's not like you can retrofit a snowthrower or lawnmower to metric fasteners. I'm better at visually identifying metric bolt head sizes than I am at SAE, and I prefer them for their logical scaling.
For cooking, I translate every recipe from USC volume measurements (cups, tablespoons, etc.) to metric weights. 500g of flour is consistent every time and doesn't vary according to how densely it's packed. Recipes can be easily scaled. Since a recipe is basically a chemical formula, it's easy to see how that relates to science and research.
For woodworking and carpentry, I use USC measurements because a) the stock sold here in the US is measured in those increments, and b) the finished product is going in a house that was built to USC measurements. For example, if I'm hanging a door or installing a window, it's manufactured in USC dimensions; the rough opening is specified in inches; the framing lumber is 1.5" x 3.5"; and the trim is dimensioned in USC as well. Using metric measurements for that project would be an exercise in masochism. This pushes all my woodworking to USC measurements because I don't want to be using two systems in the shop.
For general real-world measurements like the height of a person, the size of a room, the temperature of the air, and the capacity of a gas tank, I'm comfortable with either, but I can see why the USC system persists. The USC increments tend to be more human-scaled. A meter is pretty close to a yard; a centimeter is a bit shy of half an inch. Since I've never once encountered anyone expressing size in decimeters, this means that when you talk about the size of a room in metric measurements, you have to talk about it in what amounts to yards or half-inches, or go to decimal fractions, whereas in US measurements you might say "It's about 11 by 14 feet" and not be too far off. Ditto the height of a person; "two meters tall," rounded to the nearest whole meter, describes almost every adult human on the planet. Fahrenheit is frustrating because of its strange relationship to freezing and boiling, so Celsius has the edge there, but the Fahrenheit degrees are smaller; you can get more precision without going to fractions.
USC tends to split increments in halves, quarters, and sometimes thirds, which is more along the lines of how people think about portioning and dividing. Nobody says, "Hey, can I have five tenths of your candy bar?" People think of divisions in those terms. Tenths makes all kinds of sense for math and engineering, and I really appreciate the metric system when precise scaling is needed; but in general knocking around the world, I can understand the persistence of a system that corresponds more to the human body and habits of thought.
My two centidollars.
Oh, and as to the OP's question: I never need SAE for automotive. For other machinery, it's about 50/50.