It's become almost axiomatic that if you want to get a jump on your career, you need to start interning while you're in college, if not before.
But it's not that simple.
The pressure to land internships comes as students face a daunting job market, making the pressure for strong academic performance more intense. At the same time, rising tuition and other costs mean more students have to work to help defray expenses.
(Read more: Job picture looks bleak for 2013 college grads)
Meanwhile, lawsuits over unpaid internships are calling into question common practices for employers who use interns. (NBCUniversal, the parent company of CNBC, is among the companies being sued; it has been paying its interns since earlier this year.)
(Read more: Rallying cry against unpaid internships grows)
It also is clear that not all internships are created equal when it comes to being helpful to students. A survey of the 2013 crop of college graduates found that those with paid internships had a distinct advantage in finding jobs and being well-paid over those without internships—or with unpaid ones. In fact, unpaid internships seemed to have almost no effect on a student's success in the job market.
With all the academic pressure on students and the questions swirling around internships, does a school-year internship make sense?
Internships are almost ubiquitous on campuses. In a survey of almost 2,550 recruiters and internship program providers by the Collegiate Employment Research Institute at Michigan State University, almost 65 percent planned to offer internships. Most are for the summer, but ones during the school year are less of a rarity.
Between 10 percent and 15 percent of undergraduates at the University of Chicago have school-year internships, and the practice has become increasingly common, according to Meredith Daw, the executive director of career advancement. Five years ago, she said, perhaps 10 students had them.
Students "just want to be as competitive as possible during the application process for a full-time job," she said. "Schooltime internships are probably less competitive, so it's a really good strategy for students who want to get experience with a for-profit organization but don't have the previous experience."
(Read more: Advice to the interns: Do this, not that)
At the same time, Daw said, employers "just want to see that students are engaged," and internships clearly indicate motivation and organization. Most pay at least as much as the work-study jobs on campus, she added. That means more students can choose to pursue school-year internships—a good thing, in her view.
"Five or six years ago, you could kind of disconnect with the job process during the school year," Daw said. "Today, I don't think you can as easily. It's the same as it is for employees: You have to keep your network intact and [stay] knowledgeable in your field."
(Read more: Students give colleges 'incomplete' on job prep)
Dan Black, Americas director of recruiting at EY, the global firm that includes Ernst & Young, said internships are a great tool.
"About 50 percent of our college entry-level hires are former EY interns," he said, adding that the company pays all its interns.
Internships remain a way for employers to identify and attract the most exceptional students, Black said.
"The war for the very best talent is the worst I've ever seen it," he said. "Internships are an excellent way to secure top talent and showcase your firm, and frankly lock up some of that talent early on."
But internships—school year or otherwise—are hardly the only route to a job offer from EY.
"We also put value on other experiences that help to showcase a student's interests," Black said. "If you are a waitress or a waiter, there is a good chance you have honed the ability to deal with less-than-pleasant customers and juggle multiple demands."
If he is considering two job candidates and the only thing that differentiates them is an internship, that person will win "by a nose"—and only if the internship provided experience relevant to the job.
(Read more: Creating new strategies in war for talent)
What matters more? Academic performance, as well as a number of intangibles: "your exhibited leadership skills, a global mindset and an appreciation for a diverse workforce," Black said. "These are more important than whether you balance someone's books," he added, because they can't be taught.
—by CNBC's Kelley Holland. Follow her on Twitter