I think it has a lot to do with what juices your using, usage habits, etc.
I use cartos during the day when I'm out, etc, but I do use an HH.357 to drip and to test all my juices that I make. So I prob use my HH.357 for about an hr a day. I know that's not constant use, but I've had my HH.357 for almost 6 months and it still performs flawlessly. I've only actually fully cleaned it twice but do regularly blow it out well. I think if you use it correctly and take care of it you can def easily get your money's worth. I feel I've already gotten my money's worth and I don't see if dying any time soon. My buddy who mostly drips, but uses cartos when he's out, has been using 1 HH.357 for almost 11 months. If you stick to clearer, thinner juices it can def last a long time. The only juices I dont use with it are juices that I know contain flavoring sediments bc juices with sediments clog attys and cartos faster than anything. I use a different atty for dark juices that I know have sediments and also real thick, high VG juices.
It is def an expensive atty, but if you really use it correctly and make sure you don't neglect it, it can def last for at least a few months. Plus I find the HH.357 gives the best flavor out of any atty I've ever tried. Ive used quite a few different attys and the HH.357 picks up undertones of different flavors in a
juice that go unnoticed with alot of other attys. And it makes a LOT of vapor from little short pulls. The HH.357 works on a vacuum pump so instead of long slow pulls, you take shorter harder pulls, it's the closest I've found to how you take a drag on a cig. If you like to take slow long drags, then the HH.357 is prob not for you. But if you kinda miss how you used to take a drag on a real cig, then the HH.357 is def worth trying