I "use" chiro kind of like... hmmmm... maybe antibiotics? It's not something I'd ever consider as a "normal part of healthy living", but more of an option to treat a specific condition type thing. I was in an accident several years ago and had a wonderful chiropractor who helped me get back into shape, but once I was in shape I didn't keep going. I just kept doing my regular "healthy life" stuff.
I do know a few people who have regular chiropractic sessions, but many of them have chronic health conditions (lupus and ms specifically) that they kind of have to stay on top of. So I think for them chiropractic /is/ part of a regular health maintainance routine. But I don't think it needs to be, or even should be, for most people. Like anything, it's probably better to try and find out what is causing the "problem" that chiro is "fixing" and then addressing that. Kind of like you might use antibiotics for an accute infection but once you're feeling better you can change your diet and lifestyle to enhance your immune system and prevent future infections? For some people regular chiro (or acupuncture, or homeopathics, or massage) may be necessary, but it's probably not for most people.
Though if it feels good, and you can afford it, it certainly wont hurt! :)