For their own benefit, they should establish relationships with their professors (especially professors in their majors).

About 10% of my students regularly come to office hours to chat about class/their resumes/career opportunities, rarely miss class, and always participate. These are the students I’ll keep in touch with (this year, next year, 5 years from now…) and recommend for job opportunities when they come across my desk.

Another 25% of students raise their hands and talk in class fairly regularly. These are the students I’ll be happy to see when I run into them around campus in the future, and I’ll be happy to write them letters of recommendation if they ask.

The remaining 2/3 of students typically don’t make an effort to establish any relationship and only speak in class if/when they’re asked to. That’s perfectly fine—maybe they’ve gotten to know other professors better. But unfortunately, in six months I won’t remember them.