Maybe it's the English teacher in me, but you probably know by now I am a bit of a stickler for typographical errors.
I admit, sometimes as a teacher, I would choose NOT to ding a student on every typographical error. For one thing, students do not learn very much from that type of experience. Rather, in that situation, it was best to focus on the two or three most pressing needs at the moment and go from there. Sometimes, it was more important to me to work with the student on their message or even simply the thesis statement. If that was the case, it didn't really help them much if I also pointed out vocabulary issues.
But in working with clients in the public arena, I find there is simply NO room for error. So much is at stake whether it is the livelihood of a landscape gardener or a preacher's sermon. You need three things to succeed at this: credibility, credibility, and more credibility. And believe it or not, nothing can undercut your credibility faster than typos.
Typos remain important, even in our technological wonder age, because they reflect negatively on the writer---even when your reader is unaware of the rule being broken! When I read that highly-researched fact from a large-scale study by Andrea Lunsford and Karen Lunsford (2008), I was astounded and yet, not altogether surprised. You see, It turns out our subconscious minds are much smarter than our conscious ones. Our subconscious minds recognize typographical errors and quickly deduct a few points from your credibility account.
Make no mistake, spellcheck and grammar check save us time and therefore, money. HOWEVER, autocorrect can serve the opposite purpose. We have all had the experience of typing out a word correctly and then seeing it "corrected" to something else. So much for artificial intelligence. If you have used the word "allegory" but see it corrected to "allergy," you know. Or maybe you have chosen a slightly incorrect word and you computer does not know how to recognize your intention ( to, two, and too, anybody?).
So, with your thesaurus and spell checker take great care. When you choose a word from your thesaurus without honestly knowing its exact meaning or you let a spell checker correct spelling automatically, you may risk your credibility on a wrong-word error. If idioms and prepositions give you pause, look up the standard usage.
Howard's Hint: "Refuse to risk your credibility on a Wrong Word!"