What does your proactive maintenance schedule look like for a five-year sedan

[KevinT]

I just bought a used five-year-old sedan with a solid service history, and I want to establish a proactive car maintenance schedule to keep it running reliably for years. The owner's manual has the factory recommendations, but I've heard that real-world driving conditions might necessitate more frequent intervals for things like oil changes, brake fluid, and transmission service. For fellow DIY enthusiasts or mechanics, what does your personalized maintenance schedule look like for a modern daily driver? How do you balance the manufacturer's guidelines with more aggressive preventative care, and what are the most commonly overlooked items that can cause major problems down the line if neglected?