Monthly checks

[JohnL]

I'd recommend checking your tyres at least once a week for damage. I've lost count of the number of times I've spotted issues usually just give them a once over when I wash the car.

Oil should probably be done once a fortnight, I usually check it as well before a long journey. Not only the amount of oil but the colour of it. If it's to dark I look to get it changed.

Brake pads and discs depending on your wheels design, on mine it's very easy to see the condition of them.
Check the body for any damage ie stone chips, deep scratches

I'm sure there's others but that's all I can think of from the top of my head