Add to these features careless or ignorant writers who confuse spoken English with written English and you have a combination that could spell confusion for readers.
Take the words than and then, for instance. Both of these words appear in the example in the cropped image above. While their spelling and pronunciation is very similar, their meanings (and hence their proper uses) are quite different.
Than is an conjunction used in making comparisons (note the red underline in the cropped image). Its proper use requires two elements to appear with it, one in each side. In the example above, those two elements are the aluminum alloy 7075-T6 and 316 stainless steel. Tensile strength is the basis of the comparison.
Then is an adverb indicating sequence (note the blue underline in the cropped image). Its proper use also requires two elements, but unlike than those two elements need not be in the same phrase or even the same sentence. But they should be in the same vicinity to avoid confusion. In the example above, the two elements are what appear in sequence, namely the actions the engineer should take. First, the engineer decides what characteristics to include in the analysis. Second, the engineer creates a comparison matrix. Thus, the engineer does A, then the engineer does B.
In my experience, confusion on this point is not very common. But it is significant enough to comprise the subject of one of my weekly tips.