For years, my students wrote their assignments on paper with a pen or pencil. These days, I ask that almost everything be submitted electronically. One upshot of this is that I've learned that students either don't know or don't care about spacing around punctuation marks. Many students--typically, they tend to be writers of non-roman scripts--put no space after sentence-final punctuation, commas, semi-colons, or colons. Others put a space before these marks. I've seen open parentheses with a trailing space but no leading space and the mirror image on the other end. When everything was written by hand, these inconsistencies weren't obvious, but now they're stark.
The thing that frustrates me is that use tends to be inconsistent. The same student will write period space here, but space period there. If it were simply transfer from the first language (Japanese and Chinese, for example don't employ spaces), then you'd expect it to be consistent. You'd also think it would be quite easy to overcome, but despite my best efforts, many students continue the behaviour. The message I get is that they simply don't care. While I fight against believing this, it does get disheartening. If they can't even learn to space correctly around punctuation (if I can't even figure out how to get them to do this), then why should I believe it will be different with other aspects of their language?