Try not to attach your writing to a particular habit or tool — no matter whether it’s alcohol (the classic writer’s trap) or caffeine or chocolate; or one specific fountain pen and color of ink; or absolute silence; or the perfect comfy chair.
Because this world is fickle, and chairs break and pens and ink go out of stock, and silence is easy to get when you live alone but a lot less so once you decide to go through life in tandem or (God help you) reproduce. And as for self-indulgent habits . . . they have a nasty way of either turning on you or becoming forbidden fruit, just when you think you need them most.
When the day comes that one of your favorite things either goes away or has to be given up, your life is going to be ten times harder if you also have to figure out how to get your writing done without its aid and support.
Avoid attachment . . . that’s the ticket. Easier said than done, but then, what about this writing thing isn’t?
Dr. Doyle's Blog 
This is awesomely true and correct.