Hyphenated Last Names, need advice

I am still trying to decide what I want to do with my last name. I have heard that hyphenated names can cause administrative issues, but I was hoping for some insight from some people who have experience with these kinds of names!

Is it the length of the last name that causes issues (and the potential for misspelling or the name not fitting on forms), or the hyphen itself that causes problems? I have heard stories of some people having issues at the doctor's office, but those stories involved someone going by only one of the hyphenated names, which caused confusion.

If I hyphenated, my name would be 12 characters, including hyphen. Which is long, but I don't think is too bad? Anyone glad that they hyphenated? Regret it?