HRC press conference 260 days ago why?

That's easy. At a press conference she may encounter spontaneous questions, ie: questions that have not been submitted in advance and pre-approved by her campaign. In that case, she only has 3 answers:
1) I'll look into that
2) I will continue Obama's policy
3) DOH!

For example:

Q: Have you always been a pathological liar?
A: I'll look into that

Q: What is your plan to defeat ISIS?
A: Everything is fine, I will continue Obama's policy

Q: Have you been vindictive against Bill's lovers?
A: DOH!