Rules of thumb? They work most of the time ... as a rule of thumb.

No one can pin down exactly where and when the phrase “rule of thumb” was first used and what it was intended to mean. It first showed up in the written word in 1692. Some think it comes from cooks and brewers using their thumbs much like a new mother uses her elbow to test the temperature of cooking liquids. Probably not.

Horse heights have long been measured by “hands.” An old tailor might have once said “twice around the thumb is once around the wrist.” Many people learn to make a stride that is approximately a yard. So it is more than likely that using the space from tip of thumb to first knuckle as “about an inch” is probably the best origin for a rule of thumb.

For you and me, it is metaphor for some day-to-day tidbit that comes more from experience than from science. It’s one of those things that nine times out of 10 is dependably accurate — a ballpark estimate, a likelihood.

The first year I was in Logan, an aging neighbor told me not to plant tomatoes as long as you could see snow on the Wellsville Mountains. Well, my experience has been that that advice is a tad conservative — some nooks of snow can been seen long after the last frost that might threaten a garden — but, you know, it probably is a good rule of thumb.

Some say that to get a rough estimate for the temperature outdoors, count the number of times a lone cricket chirps in 15 seconds and add 37. Try it.

Here are some more rules of thumb that I am noticing or have heard others express recently:

— Meetings will always last longer than expected.

— Textbook publishing, oil companies and McDonalds are recession-proof. I’m just guessing on the first one based on what I see in my profession, but as far as the final two go, it’s true. You know what the oil companies are doing to us, but did you know through good business management, McDonald’s profits went up during the current recession? Higher profits for them than in 2005 or 2006. You might not like iced coffees, but somebody apparently does.

— National health care will be impossible, because of the cost. When Medicare was introduced in the 1960s, health care costs ballooned. Why do some think that just throwing more money will solve it this time?

— College sports teams always recruit “the best group ever.” Year after year.

— Hollywood will never have your best interests in mind. Oh, once in a blue moon you may catch yourself saying, “That one wasn’t so bad,” but don’t think for a moment that the popular entertainment media want to match your values and interests to theirs. We’ve been lulled into handing Hollywood the keys to our cars with basically no regulatory ropes to slow them down. Our standard of measurement has become a comparison to how bad it could have been, rather than how good it should be.

— It’s been said that the puppy to pick from the litter is the one whose tail wags in sync with its stride, a sign of calmness.

— If a person is recalling a real situation, his or her eyes tend to go up and left. You might consider that the person is making something up if his or her eyes go down and right.

— State-owned buildings will find themselves lacking in some building code or earthquake code or fire code, within five years of completion.

— Too much money and fame at too early of an age screws up your head. Just look at the Spears sisters, Miley (the fall is inevitable, trust me) and other Disney/Nickelodeon pinups for an understanding.

— Gay rights issues will always seem to dominate the news because, well, no one wants to make a fuss and become the next target, including the media.

— Alcohol makes people do stupid things.

— Fish have vertical fins, while mammals of the sea have horizontal ones.

— Ten people will raise the temperature of a medium-size room one degree per hour. (That must be why I get so warm sitting in church ... or perhaps it is the message hitting home. Hmmm.)

— For every 10 people on a committee, three will do nothing, three will say they will do something and never do it and three will do the work of the committee. The final one will never attend another meeting.

— Stock market advice should be ignored ... at least 50 percent of the time.

The same, some would suggest, could be said for reading random rules of thumb. The problem is choosing which half to ignore.