Your rent is due—that’s pretty much the only time it dawns on you: Oh, right. Checkbooks do still exist. But as mobile payment apps like Venmo and Zelle start to dominate, will the act of paying by check (and the art of balancing a checkbook, a skill I was taught with fervor by my parents when I opened my first checking account) become obsolete? We checked in with a couple of experts to find out.