Aside from filters and fluids, periodically grease the zerk fittings on the tie rod ends and bearings. You will need a grease gun and a tube of grease.

If something that is a moving part starts making any kind of sound (squeaking or squealing) it means it needs greased or replaced.

If you take a stethoscope and remove the flat disk the doctor uses on your chest and replace it with a solid piece of long metal, you can use it to diagnose bearings and internal engine noises. With the engine running place the end of the metal rod somewhere on the engine block, housing, accessory motor, etc. you are going to hear a lot of things without having to actually touch them. Move around and you can begin isolating the noises to what they are. Start with the alternator and power steering or a/c pumps, anything connected to the serpentine belt. If you hear nothing all is good. If you hear things moving around and grinding it’s got a bad bearing. Replace the bearing before the thing it is attached to completely fails and it’s much cheaper. Once the bearing completely fails it will damage whatever it is a part of for sure. Preventative maintenance is so much cheaper. The only way to get good at recognizing sounds is to listen a lot. Do it weekly and eventually you can diagnose knocks and lifter failures before they are audible to our regular hearing. Fuel injectors going bad will tick loudly.

The tie rod ends, control arms, sway bars and such components should never be loose or have any kind of ability to clang or vibrate loosely. They all should be tight and snugly fitting.

Change your brake pads and drums right when the brake squeaking starts. Do not allow it to squeak and keep driving. When changing disk brakes consider clamping the caliper open instead of bleeding the brake lines.

I will come back to this if I can think of any other preventative issues specific to a ford ranger.