Only use regular hyphen for something like fish-like. Or it might be instead of to such as: 1851 - 1873
USA and other places have two schemes for dashes using asides instead of round brackets or commas.
1. USA em dash—with no spaces
2. Many other places use en dash – with spaces
In both cases they only come in pairs, except if the aside is at the end of a sentence. Same rule as commas used as ( and ), except you always have a closing bracket even at the end of a sentence.
Both USA and elsewhere use em dash for both broken off speech (no spaces) “Watch out for mar—” He fell down the stairs after stepping on a marble.
Both USA and elsewhere use an em dash for attribution.
—Rudyard Kipling
Often but not always as above, but may be on same line —Quoth
Other sorts of dash exist, like the minus (only used in formula). Any other sort of dash should only be on paper or PDF and only specialist use (though I can't think of it).
There are two problems with less used unicode characters:
1) The default app or ereader font may not support it.
2) A user might not select an embedded font, also some apps and mobi don't support embedded fonts at all.
Summary
Never use special em dashes. Only —
Similarly special widths of spaces are recommended on paper between figures and units such as 5 lbs or 9 kg, but just use only a regular space in ebooks.
Also turn off hyphenation on source wordpocessor for ebook source and only have hypenation on version for PDF. Don't add soft hyphens. Let the user/eReader do hyphenation or not.