Forty-five years old. If I was in politics they'd call me the kid.
"The Mary Tyler Moore Show" (c. 1975)
[spoken by the character "Lou Grant,"
played by Ed Asner]

Oh, heck, I can never stop with just one quote, so here's another:

Forty-two. His age had astounded him for years, and each time that he had sat so astounded, trying to figure out what had become of the young, slim man in his twenties, a whole additional year slipped by and had to be recorded, a continually growing sum which he could not reconcile with his self-image. He still saw himself, in his mind's eye, as youthful, and when he caught sight of himself in photographs he usually collapsed ... Somebody took my actual physical presence away and substituted this, he had thought from time to time. Oh well, so it went.
Philip K. Dick
A Maze of Death (1970)

OK, that's out of the way, so...)

I find that as I get older more and more of these kinds of typos appear in my writing. I'm especially prone to typing a word that's coming up in my stream of thought in place of one that's similar in spelling or sound that I'm supposed to be typing.

Like a lot of middle-aged people, I have a tendency to interpret these errors as early indicators of Alzheimer's disease, which I think has taken over from cancer as the disease we fear the most. In my case, these fears may have some credibility, since my father's been diagnosed with Alzheimer's, so assuming there's a heritability factor involved in the disease, I might well be expected to get hit with it at some point. But whether misspelling, mistypings and petty misuses of words are really an indication of anything more serious, I can't say.

I've never gotten into the habit of using spell-check when I write, although for particularly important correspondence I do usually remember to run it through. (And since this post is at least partly about spell-checking, it'll get that treatment as well.) Even if I did, though, spell-check wouldn't catch many of the errors I make, since they involve substituting one perfectly good word for another. Style-checkers just tell me that my sentences are too long, short punchy sentences apparently being the holy grail of business correspondence. I have no idea if there's a good enough context-checker available, something that will catch "their" for "they're" or even "there", but for me by far the best thing to do is to re-read the material and check for errors -- although I find that much easier to do on paper than on a monitor. That's why for particularly important stuff, I print it out and check it off the printout. (And considering the number of mistakes I've made in the course of composing this, I might just do that this time as well.)

My wife claims that she can, generally speaking, tell a person's age from the kind of errors in their writing. People under 30, she says, have grown up with spell-checkers, so there are rarely any spelling errors in things they write, but there are frequent instances of misused (but correctly spelled words), since they're not in the habit of checking their work. If that's true, where will the next generation of copy-editors come from?

(OK, I'm finished, now to spell-check, print and re-read, and do everything possible to avoid a spelling error in a post about making spelling errors.)

(Except for misspelling "can" as "cna" and bungling "remember" in some convoluted way, what it mostly caught were hyphenations. Whatever proper usage is, I usually prefer to write "re-read" over "reread" or "re-evaluate" or "reevaluate", because I think they are clearer and easier to understand. Similarly, I rebel against putting punctuation inside quotation marks when doing so makes things more unclear. Rules are nice, and I respect them, but some are obviously simply matters of convention and are not well-founded, IMHO, Safire be damned.)

Update: I'm on the third or fourth pass through this post to correct numerous tiny mistakes which managed to survive both spell-checking and copy-editiing. Whatever is left is fair game, 'cause I give up. With Agassiz losing to Ferrero in the semi-finals at the U.S. Open, and the Yankees simultaneously being bombed by Boston, who really cares about spelling errors? There are much bigger and more important things to be concerned about, right?