Recommendation Schmecommendation

Recommendations abound in this world, suggestions on how we should take care of our stuff, what stuff we should even have and not have, and more or less on how we ought to run our lives. (Like I don't already have parents for that.)

But for today, let's just tackle the first part. We have recommended care instructions, recommended cleaning procedures, recommended maintenance schedules, recommended replacement schedules, and probably recommendations on which of those to even read first (compiled into a quick start guide). Heck, you may not even know the recommended care and maintenance stuff, because it's written in the manual, which I know most of you don't read anyhow.

So, for you: what instructions do you take as "must do" and what do you just consider recommendations induced by a company trying to make more money off of you? For instance, my dad does regular oil changes on his car, but no regular tune-ups. In fact, I think some of our cars had gone years and years without anything more than a tune-up (and changing brakes and such). They still work fine, which is enough proof to him that his approach is acceptable.

What about the recommendation that you change your toothbrush every 3 months? I had only in recent years heard that, and have cast that to the wind as a toothbrush marketing ploy. Heck, they even design bristles that change colour so that you have a nagging feeling you should be doing something about it, like that "maintenance required" indicator in your dashboards now. Sort of like how in the toothpaste commercials they always squeeze out a toothbrush-full's worth of toothpaste. I mean, what is that, like 32 tablespoons of minty fresh for you, one for each tooth??

So what's good housekeeping and what's good marketing?