Daily.
IMO, typing is like piano practice. As a matter of fact, I think they are strongly related.
I don't mean they need to sit there and practice for 1/2 hour everyday, tho'. There are typing games online. I think getting to know the keyboard so you can type without looking is a great skill. But, who knows, by the time your kids are in high school there may only be texting!
PS. I also think "shorthand" is a good thing to know. It doesn't have to be the kind old secretaries used but a way to write fast to take notes. It's served me well over the years. Make a "t" for "the" and a symbol for "and" and a dot after the root of a word for "ing". Things like that. I only use "notehand" for very common words. Also, long words that are repeated throughout a session, say "environment" is used for a paper or lecture. I would write "
environment" the first time and just use the underlined "
e" for the rest of the paper.
You are far from that, tho'.