The love affair.
To be a writer is like growing old with the love of your life while keeping the constant flow of mutual inspiration and passion.
To be a writer, it's not enough to just love writing. You have to have a constant love affair with it. To want to sneak in writing whenever you can. Even if only for a moment to take a few notes.
As your writing matures, and becomes a steady part of your life, your urge to write matures with it. Like in a long relationship, the love affair takes another form and gains bigger depth, but it doesn't stop.
It's always there as a constant flow of inspiration and passion, and writing is the same. You must grow with writing like you grow with love.