Well meant advice, but do it the way you want to! Sounds like changing projects keeps you from getting bored and giving up the whole hobby. There are no rules! Do what works for you.
When I'm working on a project I give it from 2 to 4 hours a day, usually. Sometimes other obligations or duties interfere (the house will not clean itself no matter how long I wait, I've realized!). I used to sew a lot while working full time -- would come home, cut out a dress, sew it, and wear it the next day -- but I don't have that energy or dedication any longer. I admire those of you who can find time for quilt making while working full time and having a family. Pretty sure I couldn't do that, so I'm glad I waited until retirement to take up this hobby.