There are 365 days in a year....

...you can write one sentence every day. Two if you really really have to get it down right then and there. More, if you have the time to do so.
Next year this time you'll have 365 sentences on paper.
How many pages does that equate to? No idea!
The point is that you write, a little bit, a lot, every single day. Make it a habit if you don't have time.
Make it routine if you're not inspired. Make it part of your day, your life, like eating or drinking.
Stop writing in your head and start writing on paper.
May the savior be with you on your journey.
May the force be with you.
And all that.

Happy writing and reading.