The amount of people who don't do the absolute bear minimum to check their car isn't in safe order is astounding.
I'd hate to find my car overheated on the hard shoulder with two kids in it because I didn't bother to check the coolant level.
I'd hate to find my engine seized up at 70mph on the motorway, with or without my kids in it! The loss of control would be catastrophic.
I'd hate to find that my brakes had failed completely because the fluid level had dropped below the level of the master cylinder. Disastrous.
I'd hate to try to pull an emergency stop only to find my tyres were out of tread.
"the cars in decent condition so it shouldn't need checking often"
Dear lord, the car won't be in good condition if you don't check these things often. Any new car can burst a hose and lose coolant. Any new car can get an oil leak.
It costs nothing to check your car over, but it could cost you your life, the life of anyone else in the car, or the life of a pedestrian or other road user if you don't. A lot can change in the 12 months between MOT's.
FFS. The ignorance here is astonishing.