On some days, the prose flows effortlessly. On others, every word is hard-won.

Writer’s block. It’s something every single writer has experienced before, whether you’re Jane Smiley or a journalist or simply a high schooler trying to finish your essay at 2 a.m. on the day it’s due.

When I was that teenaged night owl, I’d ask myself (and to whichever classmate was still logged on to AOL Instant Messenger) whether writing, already a labor of love for me, would ever get easier. Would New Yorker-quality essays, maybe even Pulitzer-worthy novels, someday leap straight from my mind to the page in a feverish stroke of creativity? What was it that master authors possessed that I did not, and was it a skill I could acquire in school or with practice?

When I got into my twenties, I somehow assumed that, with all the writing practice I was getting at newspapers up and down the West Coast, things really would get easier. But I’m not sure why, given I worked in breaking news, which meant that nearly everything I covered required me to learn something new every day. I’d spend every single day figuring out how to use a new-to-me word or phrase in a sentence (barometric pressure, arraignment, emoluments clause). Yet I still believed the learning might stop someday, that I’d arrive at a point where I’d just know everything.

Well, I’m in my early thirties now, and as it turns out, I don’t know everything. In fact, I’ve grown increasingly aware of just how little I know. So I can say with near certainty that effortlessly good writing doesn’t naturally develop with enough practice and training. My writing is demonstrably better than it was when I was 20, but do I exert any less effort to produce it? No.

As I enter the third decade of my life, I’m increasingly convinced that the most important things great writers possess are good story ideas and unique life experiences — and you can’t pick those up in school. Strip that all away and, yes, you’d still have beautiful prose. But are those words easily conjured, or are they labored over? Given what I’ve read and seen of author interviews over the years, I think the latter is true more often than not.

Think about this:

• Bestselling authors typically aim to write 1,000 to 2,000 words a day, with the incredibly prolific Anne Rice types clocking in at 3,000. That’s about 2-6 pages.

• Ernest Hemingway is famous for writing just 500 words a day on average. He once said, “We are all apprentices in a craft where no one ever becomes a master.”

• It took nine years for Jeffery Eugenides to release another book after “The Virgin Suicides.” That book was “Middlesex,” and it won the Pulitzer Prize.

Even those who make a living doing nothing but writing rack up a daily word count that’s about as long as your average high school essay. I imagine they might churn out the words faster if writing really were effortless for them.

I thought about this the other day while biking to work. When I first started commuting by cycle, I cursed my unconditioned quads and wondered to myself: When will this get easier? Two years later, I had quads of steel — but I still gasped for breath on every hill. I had to dive into the stats to understand why. In those early months of bike commuting, it took me about 22 minutes to traverse the few miles from home to work. These days, I average more like 15-18 minutes.

It doesn’t get easier. You just get better. As it goes with biking, so it goes with writing.