For me my biggest constraints are financial, space, and time. I am young enough I work 40-60 hour weeks, with an hour commute daily. Adding housework and basic self care into the mix and I have maybe 20 minutes a day to work on my hobbies. For years and years and years I could never make myself dig everything out of the closet, set it up on the kitchen table to sew for five minutes, then put it all back. I did, however, continue looking and dreaming. I have entire notebooks of hand colored quilt projects I will never make, because that was as close as I could get to quilting.
Now that I'm a little older and more established at work, I have a bigger place (the sewing machine lives on a desk and not the closet floor!), and more money to spend on fabric. I still have to watch my spending, but a year of careful saving can get me a lot of fabric on black friday. Not really able to find fabric second hand here, I have never seen it at any thrift store, and I always work on garage sale days. I usually plan 4-5 larger projects for next year while I work on what I have now, and buy the fabric all at once while it is on deep discount.
It's taken me a long time to get myself set up so I can actually quilt as a hobby. I am grateful that I have gotten this far, and I make it a point to take my time and enjoy my hobby and build my skills, instead of rushing through life to get it done and move onto the next project.
I don't regret the dreaming about things I will never make it; it made me happy, and over time i really learned what I do and do not like in designs and color, etc. Now I'm just working towards learning everything I can to make some of those dreams a reality!