As an author it's hard to balance your time spent writing against your time spent promoting. Most of us get into this business because we like to write, not because we're salespeople and want to sit behind a table trying to hand sell our books.
It's a package deal, so you learn what events work best for you.
I tend to say yes to everything, even things I know probably won't be lucrative. I have reasons for this, and I explain in this month's podcast roundup.
As always, if you find the podcast helpful, rating and reviewing on iTunes is much appreciated!