What's the compensation like for 10+ hours of work?
source: been there, asked for feedback after received just a generic "No good luck with you career" and no response for my email..
That's worth possibly negotiating the amount of time or staging earlier parts with less impact.
I wouldn't say no to an interview that is going to burn a day, but I also wouldn't go to one without a pretty good feeling that I was likely to accept an offer if it came.
I mostly think of interviews as at least as much of a chance for me to evaluate them as the other way around (even the way they choose to interview tells me a lot).
There is no reason that you can't have a mature interaction with a company where you both agree to invest some time and effort in a process that could benefit both of you. If it looks like a bad risk to you, don't go. If you are doing a competent job of this, you should know what an interview process looks like before you agree to the interview. If there are aspect of it you aren't sure about, you should ask about them. If their reasoning doesn't convince you - respectfully decline the interview.
The most valuable thing about an interview process is an exchange of information. Thinking about it too much as a time-for-money trade off can miss this point. Of course, if you can find a more time efficient way to exchange the same information, that's good all around.