The sign that it won't be for me: When it ceases to be fun.
I shoot some of everything, and it's all got it's place. I like the results from film, but I also enjoy the process. If the day comes when it's no longer fun, I'll just quit doing it...or take a break. I've had a few hobbies I've taken a couple of years off of because I was losing interest. Came back a couple years later and it was fun again . I don't shoot a ton of LF, but I always enjoy it when I do.