I try to use good judgment. I also stick close to the owners manual. If the manual says do it, you had better do it, at least while still in warranty even if you don't see any need. Been around long enough to see a lot of rubber stuff eventually fail, hoses of all kinds, windshield wipers, tires, caliper seals and boots, pencil erasers, etc. There was a thread recently about when to change radiator hoses. I try to think to check mine now and then, and is the upper one is spongy change it, the lower, and the bypass. Last fall I did the coolant in my truck too.
On the other hand, I am leaving the platinum tip spark plugs in the aluminum head to the 100K my owners manual says. I have never changed brake fluid as such. After I do preventive maintenance on the calipers, there isn't much of the old stuff left. The rubber boot on a caliper may still look good, but it is hard to tell if it has lost its snap or gotten too hard to keep the yuck away from the expensive piston. When I rebuilt calipers for a living, I saw many frozen or leaking ones that the boot still looked good. The piston always had a big gob of rust on the outer part.
Some things you are going to do sooner or later. May as well be at home in the garage when you have time for it. Other things are best left alone.
Best to work up to more challenging projects as you aquire experience.
If you don't have the old bleed screws out yet, see
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=24;t=000035#000000
*iatrogenic (iatro- + Gr. gennan to produce) resulting from the activity of physicians. Originally applied to disorders induced in the patient by autosuggestion based on the physician's examination, manner, or discussion, the term is now applied to any adverse condition in a patient occurring as the result of treatment by a physician or surgeon, especially to infections acquired by the patient during the course of treatment. Cf. nosocomial.
