Depends on the size of the feature, and the maintainer, but you're right about "talk to the maintainter." Some projects, you'll want to do a weekend of really

Depends on the size of the feature, and the maintainer, but you're right about "talk to the maintainter." Some projects, you'll want to do a weekend of really rough work, contact the maintainer, get their thoughts. Others, you'll want to do 8 days work, get it far enough along to show, get their thoughts. Often though, before you write a line of code, talk to them.