I'll echo this. Before I went into consulting I would interview bimonthly or so. Not because I was unhappy (though sometimes I was), but because it was good to keep sharp and because sometimes you'll surprise yourself by finding a gig that really clicks. I was a lousy interview at my first job out of college. I've been a very good one since, and it's helped me get jobs I liked.
It's also helped me seriously expand my network (and Boston's a small town); you meet a lot of people.
Not purely randomly, I only interview at places I think I might want to work, but most of it is from inbound requests via LinkedIn. My LinkedIn profile is recruiter catnip, which helps. I've gone from Trendy Area to Trendy Area (and I'm fortunate that doing so brought me into devops/platform engineering, which I really like!) and I still get hits for mobile/Android gigs despite not touching it since before Android Studio was released.
So if a company sounds interesting, sure, I'll go talk to them. I don't actively seek them out, but they tend to find me. (And even if I don't find them particularly compelling, I might be able to sell them on consulting services.)
It's also helped me seriously expand my network (and Boston's a small town); you meet a lot of people.