Not as well as I would like. A few years ago, my diet was amazing and I was getting daily exercise, and that felt really good. I moved in with my partner last year, who is extremely picky and rejects most dishes I make that are healthy. So I cook meals we can agree on, which often end up being devoid of vegetables and either unhealthy or neutral at best.
I also now get woken up an hour before I'd like to, at 5 a.m., by a screaming cat every single morning, so instead of exercising or doing yoga before work, I just spend the next two hours being exhausted and just trying to wake up.
I'm good about other things, like skincare and not staying up late. The state of my living space also correlates directly with my mental state, so I always keep things clean.
I think, I hope, that building routines aren't linear. At 17 and 18 I had great routines too which fell by the wayside the longer I spent in college, and things got better for a few years after college. Cohabitating with another person will be a temporary setback and not a permanent one.